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Matter L, Abdullaeva OS, Shaner S, Leal J, Asplund M. Bioelectronic Direct Current Stimulation at the Transition Between Reversible and Irreversible Charge Transfer. Adv Sci (Weinh) 2024:e2306244. [PMID: 38460180 DOI: 10.1002/advs.202306244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 02/06/2024] [Indexed: 03/11/2024]
Abstract
Many biological processes rely on endogenous electric fields (EFs), including tissue regeneration, cell development, wound healing, and cancer metastasis. Mimicking these biological EFs by applying external direct current stimulation (DCS) is therefore the key to many new therapeutic strategies. During DCS, the charge transfer from electrode to tissue relies on a combination of reversible and irreversible electrochemical processes, which may generate toxic or bio-altering substances, including metal ions and reactive oxygen species (ROS). Poly(3,4-ethylenedioxythiophene) (PEDOT) based electrodes are emerging as suitable candidates for DCS to improve biocompatibility compared to metals. This work addresses whether PEDOT electrodes can be tailored to favor reversible biocompatible charge transfer. To this end, different PEDOT formulations and their respective back electrodes are studied using cyclic voltammetry, chronopotentiometry, and direct measurements of H2 O2 and O2 . This combination of electrochemical methods sheds light on the time dynamics of reversible and irreversible charge transfer and the relationship between capacitance and ROS generation. The results presented here show that although all electrode materials investigated generate ROS, the onset of ROS can be delayed by increasing the electrode's capacitance via PEDOT coating, which has implications for future bioelectronic devices that allow longer reversibly driven pulse durations during DCS.
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Affiliation(s)
- Lukas Matter
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, Gothenburg, SE 41296, Sweden
- Department of Microsystems Engineering, University of Freiburg, Georges-Köhler-Allee 201, 79110, Freiburg, Germany
- Brainlinks-Braintools Center, University of Freiburg, Georges-Köhler-Allee 201, 79110, Freiburg, Germany
- Freiburg Institute for Advanced Studies (FRIAS), University of Freiburg, Albertstraße 19, 79104, Freiburg, Germany
| | - Oliya S Abdullaeva
- Division of Nursing and Medical Technology, Luleå University of Technology, Luleå, SE 97187, Sweden
| | - Sebastian Shaner
- Department of Microsystems Engineering, University of Freiburg, Georges-Köhler-Allee 201, 79110, Freiburg, Germany
- Brainlinks-Braintools Center, University of Freiburg, Georges-Köhler-Allee 201, 79110, Freiburg, Germany
| | - José Leal
- Department of Microsystems Engineering, University of Freiburg, Georges-Köhler-Allee 201, 79110, Freiburg, Germany
- Brainlinks-Braintools Center, University of Freiburg, Georges-Köhler-Allee 201, 79110, Freiburg, Germany
| | - Maria Asplund
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, Gothenburg, SE 41296, Sweden
- Department of Microsystems Engineering, University of Freiburg, Georges-Köhler-Allee 201, 79110, Freiburg, Germany
- Brainlinks-Braintools Center, University of Freiburg, Georges-Köhler-Allee 201, 79110, Freiburg, Germany
- Freiburg Institute for Advanced Studies (FRIAS), University of Freiburg, Albertstraße 19, 79104, Freiburg, Germany
- Division of Nursing and Medical Technology, Luleå University of Technology, Luleå, SE 97187, Sweden
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Lewis CM, Boehler C, Liljemalm R, Fries P, Stieglitz T, Asplund M. Recording Quality Is Systematically Related to Electrode Impedance. Adv Healthc Mater 2024:e2303401. [PMID: 38354063 DOI: 10.1002/adhm.202303401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Revised: 01/19/2024] [Indexed: 02/16/2024]
Abstract
Extracellular recordings with planar microelectrodes are the gold standard technique for recording the fast action potentials of neurons in the intact brain. The introduction of microfabrication techniques has revolutionized the in vivo recording of neuronal activity and introduced high-density, multi-electrode arrays that increase the spatial resolution of recordings and the number of neurons that can be simultaneously recorded. Despite these innovations, there is still debate about the ideal electrical transfer characteristics of extracellular electrodes. This uncertainty is partly due to the lack of systematic studies comparing electrodes with different characteristics, particularly for chronically implanted arrays over extended time periods. Here a high-density, flexible, and thin-film array is fabricated and tested, containing four distinct electrode types differing in surface material and surface topology and, thus, impedance. It is found that recording quality is strongly related to electrode impedance with signal amplitude and unit yield negatively correlated to impedance. Electrode impedances are stable for the duration of the experiment (up to 12 weeks) and recording quality does not deteriorate. The findings support the expectation from the theory that recording quality will increase as impedance decreases.
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Affiliation(s)
| | - Christian Boehler
- Department of Microsystems Engineering (IMTEK), University of Freiburg, 79110, Freiburg, Germany
- BrainLinks-BrainTools Center, University of Freiburg, 79110, Freiburg, Germany
| | - Rickard Liljemalm
- Department of Microsystems Engineering (IMTEK), University of Freiburg, 79110, Freiburg, Germany
| | - Pascal Fries
- Ernst Strüngmann Institute (ESI) for Neuroscience in Cooperation with Max Planck Society, Deutschordenstraße 46, 60528, Frankfurt, Germany
- Donders Institute for Brain, Cognition and Behaviour, Radboud University, Kapittelweg 29, 6525 EN, Nijmegen, Netherland
| | - Thomas Stieglitz
- Department of Microsystems Engineering (IMTEK), University of Freiburg, 79110, Freiburg, Germany
- BrainLinks-BrainTools Center, University of Freiburg, 79110, Freiburg, Germany
| | - Maria Asplund
- Department of Microsystems Engineering (IMTEK), University of Freiburg, 79110, Freiburg, Germany
- BrainLinks-BrainTools Center, University of Freiburg, 79110, Freiburg, Germany
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, Kemivägen 9, Gothenburg, 41258, Sweden
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Orlemann C, Boehler C, Kooijmans RN, Li B, Asplund M, Roelfsema PR. Flexible Polymer Electrodes for Stable Prosthetic Visual Perception in Mice. Adv Healthc Mater 2024:e2304169. [PMID: 38324245 DOI: 10.1002/adhm.202304169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Revised: 02/01/2024] [Indexed: 02/08/2024]
Abstract
Brain interfaces that can stimulate neurons, cause minimal damage, and work for a long time will be central for future neuroprosthetics. Here, the long-term performance of highly flexible, thin polyimide shanks with several small (<15 µm) electrodes during electrical microstimulation of the visual cortex, is reported. The electrodes exhibit a remarkable stability when several billions of electrical pulses are applied in vitro. When the devices are implanted in the primary visual cortex (area V1) of mice and the animals are trained to detect electrical microstimulation, it is found that the perceptual thresholds are 2-20 microamperes (µA), which is far below the maximal currents that the electrodes can withstand. The long-term functionality of the devices in vivo is excellent, with stable performance for up to more than a year and little damage to the brain tissue. These results demonstrate the potential of thin floating electrodes for the long-term restoration of lost sensory functions.
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Affiliation(s)
- Corinne Orlemann
- Department of Vision and Cognition, Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences, Amsterdam, 1105 BA, The Netherlands
| | - Christian Boehler
- Department of Microsystems Engineering (IMTEK), University of Freiburg, 79110, Freiburg, Germany
- BrainLinks-BrainTools Center, University of Freiburg, 79110, Freiburg, Germany
| | - Roxana N Kooijmans
- Department of Vision and Cognition, Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences, Amsterdam, 1105 BA, The Netherlands
- Institute for Neuroscience and Medicine (INM-1), Forschungszentrum Jülich, 52428, Jülich, Germany
| | - Bingshuo Li
- Department of Vision and Cognition, Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences, Amsterdam, 1105 BA, The Netherlands
| | - Maria Asplund
- Department of Microsystems Engineering (IMTEK), University of Freiburg, 79110, Freiburg, Germany
- BrainLinks-BrainTools Center, University of Freiburg, 79110, Freiburg, Germany
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, Gothenburg, 412 96, Sweden
| | - Pieter R Roelfsema
- Department of Vision and Cognition, Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences, Amsterdam, 1105 BA, The Netherlands
- Laboratory of Visual Brain Therapy, Sorbonne Université, Institut National de la Santé et de la Recherche Médicale, Centre National de la Recherche Scientifique, Institut de la Vision, Paris, F-75012, France
- Department of Integrative Neurophysiology, Centre for Neurogenomics and Cognitive Research, VU University, Amsterdam, 1081 HV, The Netherlands
- Department of Neurosurgery, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, 1105 AZ, The Netherlands
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Shaner S, Lu H, Lenz M, Garg S, Vlachos A, Asplund M. Brain stimulation-on-a-chip: a neuromodulation platform for brain slices. Lab Chip 2023; 23:4967-4985. [PMID: 37909911 PMCID: PMC10661668 DOI: 10.1039/d3lc00492a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Accepted: 10/15/2023] [Indexed: 11/03/2023]
Abstract
Electrical stimulation of ex vivo brain tissue slices has been a method used to understand mechanisms imparted by transcranial direct current stimulation (tDCS), but there are significant direct current electric field (dcEF) dosage and electrochemical by-product concerns in conventional experimental setups that may impact translational findings. Therefore, we developed an on-chip platform with fluidic, electrochemical, and magnetically-induced spatial control. Fluidically, the chamber geometrically confines precise dcEF delivery to the enclosed brain slice and allows for tissue recovery in order to monitor post-stimulation effects. Electrochemically, conducting hydrogel electrodes mitigate stimulation-induced faradaic reactions typical of commonly-used metal electrodes. Magnetically, we applied ferromagnetic substrates beneath the tissue and used an external permanent magnet to enable in situ rotational control in relation to the dcEF. By combining the microfluidic chamber with live-cell calcium imaging and electrophysiological recordings, we showcased the potential to study the acute and lasting effects of dcEFs with the potential of providing multi-session stimulation. This on-chip bioelectronic platform presents a modernized yet simple solution to electrically stimulate explanted tissue by offering more environmental control to users, which unlocks new opportunities to conduct thorough brain stimulation mechanistic investigations.
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Affiliation(s)
- Sebastian Shaner
- Department of Microsystems Engineering, University of Freiburg, Georges-Köhler-Allee 103, 79110 Freiburg im Breisgau, Germany
- BrainLinks-BrainTools Center, University of Freiburg, Georges-Köhler-Allee 201, 79110 Freiburg im Breisgau, Germany
| | - Han Lu
- BrainLinks-BrainTools Center, University of Freiburg, Georges-Köhler-Allee 201, 79110 Freiburg im Breisgau, Germany
- Department of Neuroanatomy, Institute of Anatomy and Cell Biology, Faculty of Medicine, University of Freiburg, Albertstraße 17, 79104 Freiburg im Breisgau, Germany.
| | - Maximilian Lenz
- Department of Neuroanatomy, Institute of Anatomy and Cell Biology, Faculty of Medicine, University of Freiburg, Albertstraße 17, 79104 Freiburg im Breisgau, Germany.
- Hannover Medical School, Institute of Neuroanatomy and Cell Biology, Carl-Neuberg-Straße 1, 30625 Hannover, Germany
| | - Shreyash Garg
- Department of Neuroanatomy, Institute of Anatomy and Cell Biology, Faculty of Medicine, University of Freiburg, Albertstraße 17, 79104 Freiburg im Breisgau, Germany.
- MSc Neuroscience Program, Faculty of Biology, University of Freiburg, Schänzlestraße 1, 79104 Freiburg im Breisgau, Germany
| | - Andreas Vlachos
- BrainLinks-BrainTools Center, University of Freiburg, Georges-Köhler-Allee 201, 79110 Freiburg im Breisgau, Germany
- Department of Neuroanatomy, Institute of Anatomy and Cell Biology, Faculty of Medicine, University of Freiburg, Albertstraße 17, 79104 Freiburg im Breisgau, Germany.
- Center for Basics in Neuromodulation (NeuroModulBasics), Faculty of Medicine, University of Freiburg, 79104 Freiburg im Breisgau, Germany
| | - Maria Asplund
- Department of Microsystems Engineering, University of Freiburg, Georges-Köhler-Allee 103, 79110 Freiburg im Breisgau, Germany
- BrainLinks-BrainTools Center, University of Freiburg, Georges-Köhler-Allee 201, 79110 Freiburg im Breisgau, Germany
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, Chalmersplatsen 4, 41258 Gothenburg, Sweden.
- Division of Nursing and Medical Technology, Luleå University of Technology, 79187 Luleå, Sweden
- Freiburg Institute for Advanced Studies (FRIAS), University of Freiburg, Albertstraße 19, 79104 Freiburg im Breisgau, Germany
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Barnes CJ, Clausen ML, Asplund M, Rasmussen L, Olesen CM, Yüksel YT, Andersen PS, Litman T, Hansen AJ, Agner T. Erratum for Barnes et al., "Temporal and Spatial Variation of the Skin-Associated Bacteria From Healthy Participants and Atopic Dermatitis Patients". mSphere 2023; 8:e0031923. [PMID: 37768054 PMCID: PMC10654186 DOI: 10.1128/msphere.00319-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/29/2023] Open
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6
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Barnes CJ, Asplund M, Clausen ML, Rasmussen L, Olesen CM, Yüksel YT, Andersen PS, Litman T, Holmstrøm K, Bay L, Fritz BG, Bjarnsholt T, Agner T, Hansen AJ. A simplified bacterial community found within the epidermis than at the epidermal surface of atopic dermatitis patients and healthy controls. BMC Microbiol 2023; 23:273. [PMID: 37773096 PMCID: PMC10540355 DOI: 10.1186/s12866-023-03012-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Accepted: 09/11/2023] [Indexed: 09/30/2023] Open
Abstract
There has been considerable research into the understanding of the healthy skin microbiome. Similarly, there is also a considerable body of research into whether specific microbes contribute to skin disorders, with atopic dermatitis (AD) routinely linked to increased Staphylococcus aureus (S. aureus) colonisation. In this study, the epidermal surface of participants was sampled using swabs, while serial tape-stripping (35 tapes) was performed to sample through the stratum corneum. Samples were taken from AD patients and healthy controls, and the bacterial communities were profiled by metabarcoding the universal V3-V4 16S rRNA region. Results show that the majority of bacterial richness is located within the outermost layers of the stratum corneum, however there were many taxa that were found almost exclusively at the very outermost layer of the epidermis. We therefore hypothesise that tape-stripping can be performed to investigate the 'core microbiome' of participants by removing environmental contaminants. Interestingly, significant community variation between AD patients and healthy controls was only observable at the epidermal surface, yet a number of individual taxa were found to consistently differ with AD status across the entire epidermis (i.e. both the epidermal surface and within the epidermis). Sampling strategy could therefore be tailored dependent on the hypothesis, with sampling for forensic applications best performed using surface swabs and outer tapes, while profiling sub-surface communities may better reflect host genome and immunological status.
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Affiliation(s)
- Christopher J Barnes
- The Globe Institute, Faculty of Health, University of Copenhagen, Copenhagen K, 1350, Denmark.
- Department of Agroecology, Faculty of Technical Sciences, Aarhus University, Forsøgsvej 1, Slagelse, 4200, Denmark.
| | - Maria Asplund
- The Globe Institute, Faculty of Health, University of Copenhagen, Copenhagen K, 1350, Denmark
| | - Maja-Lisa Clausen
- Department of Dermatology, Bispebjerg Hospital, University of Copenhagen, Copenhagen, Denmark
| | - Linett Rasmussen
- The Globe Institute, Faculty of Health, University of Copenhagen, Copenhagen K, 1350, Denmark
| | - Caroline Meyer Olesen
- Department of Dermatology, Bispebjerg Hospital, University of Copenhagen, Copenhagen, Denmark
| | - Yasemin Topal Yüksel
- Department of Dermatology, Bispebjerg Hospital, University of Copenhagen, Copenhagen, Denmark
| | - Paal Skytt Andersen
- Department of Bacteria, Parasites and Fungi, Statens Serum Insitute, Copenhagen, Denmark
| | - Thomas Litman
- Department of Immunology and Microbiology, LEO Foundation Skin Immunology Research Center, University of Copenhagen, Copenhagen, Denmark
- Explorative Biology and Bioinformatics, LEO Pharma A/S, Ballerup, Denmark
| | | | - Lene Bay
- Costerton Biofilm Center, Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
| | - Blaine Gabriel Fritz
- Costerton Biofilm Center, Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
| | - Thomas Bjarnsholt
- Costerton Biofilm Center, Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
| | - Tove Agner
- Department of Dermatology, Bispebjerg Hospital, University of Copenhagen, Copenhagen, Denmark
| | - Anders Johannes Hansen
- The Globe Institute, Faculty of Health, University of Copenhagen, Copenhagen K, 1350, Denmark
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Matter L, Harland B, Raos B, Svirskis D, Asplund M. Generation of direct current electrical fields as regenerative therapy for spinal cord injury: A review. APL Bioeng 2023; 7:031505. [PMID: 37736015 PMCID: PMC10511262 DOI: 10.1063/5.0152669] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Accepted: 08/21/2023] [Indexed: 09/23/2023] Open
Abstract
Electrical stimulation (ES) shows promise as a therapy to promote recovery and regeneration after spinal cord injury. ES therapy establishes beneficial electric fields (EFs) and has been investigated in numerous studies, which date back nearly a century. In this review, we discuss the various engineering approaches available to generate regenerative EFs through direct current electrical stimulation and very low frequency electrical stimulation. We highlight the electrode-tissue interface, which is important for the appropriate choice of electrode material and stimulator circuitry. We discuss how to best estimate and control the generated field, which is an important measure for comparability of studies. Finally, we assess the methods used in these studies to measure functional recovery after the injury and treatment. This work reviews studies in the field of ES therapy with the goal of supporting decisions regarding best stimulation strategy and recovery assessment for future work.
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Affiliation(s)
- Lukas Matter
- Author to whom correspondence should be addressed:
| | - Bruce Harland
- School of Pharmacy, The University of Auckland, NZ 1023 Auckland, New Zealand
| | - Brad Raos
- School of Pharmacy, The University of Auckland, NZ 1023 Auckland, New Zealand
| | - Darren Svirskis
- School of Pharmacy, The University of Auckland, NZ 1023 Auckland, New Zealand
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Leal J, Shaner S, Jedrusik N, Savelyeva A, Asplund M. Electrotaxis evokes directional separation of co-cultured keratinocytes and fibroblasts. Sci Rep 2023; 13:11444. [PMID: 37454232 PMCID: PMC10349865 DOI: 10.1038/s41598-023-38664-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Accepted: 07/12/2023] [Indexed: 07/18/2023] Open
Abstract
Bioelectric communication plays a significant role in several cellular processes and biological mechanisms, such as division, differentiation, migration, cancer metastasis, and wound healing. Ion flow across cellular walls leads to potential gradients and subsequent formation of constant or time-varying electric fields(EFs), which regulate cellular processes. An EF is natively generated towards the wound center during epithelial wound healing, aiming to align and guide cell migration, particularly of macrophages, fibroblasts, and keratinocytes. While this phenomenon, known as electrotaxis or galvanotaxis, has been extensively investigated across many cell types, it is typically explored one cell type at a time, which does not accurately represent cellular interactions during complex biological processes. Here we show the co-cultured electrotaxis of epidermal keratinocytes and dermal fibroblasts with a salt-bridgeless microfluidic approach for the first time. The electrotactic response of these cells was first assessed in mono-culture to establish a baseline, resulting in the characteristic cathodic migration for keratinocytes and anodic for fibroblasts. Both cell types retained their electrotactic properties in co-culture leading to clear cellular partition even in the presence of cellular collisions. The methods leveraged here pave the way for future co-culture electrotaxis experiments where the concurrent influence of cell types can be thoroughly investigated.
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Affiliation(s)
- José Leal
- Department of Microsystems Engineering (IMTEK), University of Freiburg, Freiburg, Germany.
- BrainLinks-BrainTools Center, University of Freiburg, Freiburg, Germany.
| | - Sebastian Shaner
- Department of Microsystems Engineering (IMTEK), University of Freiburg, Freiburg, Germany
- BrainLinks-BrainTools Center, University of Freiburg, Freiburg, Germany
| | - Nicole Jedrusik
- Department of Microsystems Engineering (IMTEK), University of Freiburg, Freiburg, Germany
- BrainLinks-BrainTools Center, University of Freiburg, Freiburg, Germany
| | - Anna Savelyeva
- Department of Microsystems Engineering (IMTEK), University of Freiburg, Freiburg, Germany
- BrainLinks-BrainTools Center, University of Freiburg, Freiburg, Germany
| | - Maria Asplund
- Department of Microsystems Engineering (IMTEK), University of Freiburg, Freiburg, Germany.
- BrainLinks-BrainTools Center, University of Freiburg, Freiburg, Germany.
- Freiburg Institute for Advanced Studies (FRIAS), University of Freiburg, Freiburg, Germany.
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, Gothenburg, Sweden.
- Division of Nursing and Medical Technology, Luleå University of Technology, 97187, Luleå, Sweden.
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Chen X, Wang F, Kooijmans R, Klink PC, Boehler C, Asplund M, Roelfsema PR. Chronic stability of a neuroprosthesis comprising multiple adjacent Utah arrays in monkeys. J Neural Eng 2023; 20:036039. [PMID: 37386891 DOI: 10.1088/1741-2552/ace07e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Accepted: 06/21/2023] [Indexed: 07/01/2023]
Abstract
Objective. Electrical stimulation of visual cortex via a neuroprosthesis induces the perception of dots of light ('phosphenes'), potentially allowing recognition of simple shapes even after decades of blindness. However, restoration of functional vision requires large numbers of electrodes, and chronic, clinical implantation of intracortical electrodes in the visual cortex has only been achieved using devices of up to 96 channels. We evaluated the efficacy and stability of a 1024-channel neuroprosthesis system in non-human primates (NHPs) over more than 3 years to assess its suitability for long-term vision restoration.Approach.We implanted 16 microelectrode arrays (Utah arrays) consisting of 8 × 8 electrodes with iridium oxide tips in the primary visual cortex (V1) and visual area 4 (V4) of two sighted macaques. We monitored the animals' health and measured electrode impedances and neuronal signal quality by calculating signal-to-noise ratios of visually driven neuronal activity, peak-to-peak voltages of the waveforms of action potentials, and the number of channels with high-amplitude signals. We delivered cortical microstimulation and determined the minimum current that could be perceived, monitoring the number of channels that successfully yielded phosphenes. We also examined the influence of the implant on a visual task after 2-3 years of implantation and determined the integrity of the brain tissue with a histological analysis 3-3.5 years post-implantation.Main results. The monkeys remained healthy throughout the implantation period and the device retained its mechanical integrity and electrical conductivity. However, we observed decreasing signal quality with time, declining numbers of phosphene-evoking electrodes, decreases in electrode impedances, and impaired performance on a visual task at visual field locations corresponding to implanted cortical regions. Current thresholds increased with time in one of the two animals. The histological analysis revealed encapsulation of arrays and cortical degeneration. Scanning electron microscopy on one array revealed degradation of IrOxcoating and higher impedances for electrodes with broken tips.Significance. Long-term implantation of a high-channel-count device in NHP visual cortex was accompanied by deformation of cortical tissue and decreased stimulation efficacy and signal quality over time. We conclude that improvements in device biocompatibility and/or refinement of implantation techniques are needed before future clinical use is feasible.
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Affiliation(s)
- Xing Chen
- Department of Vision and Cognition, Netherlands Institute for Neuroscience, Meibergdreef 47, 1105 BA Amsterdam, The Netherlands
- Department of Ophthalmology, University of Pittsburgh School of Medicine, 1622 Locust St, Pittsburgh, PA 15219, United States of America
| | - Feng Wang
- Department of Vision and Cognition, Netherlands Institute for Neuroscience, Meibergdreef 47, 1105 BA Amsterdam, The Netherlands
| | - Roxana Kooijmans
- Department of Vision and Cognition, Netherlands Institute for Neuroscience, Meibergdreef 47, 1105 BA Amsterdam, The Netherlands
| | - Peter Christiaan Klink
- Department of Vision and Cognition, Netherlands Institute for Neuroscience, Meibergdreef 47, 1105 BA Amsterdam, The Netherlands
- Experimental Psychology, Helmholtz Institute, Utrecht University, Utrecht, The Netherlands
- Laboratory of Visual Brain Therapy, Sorbonne Université, Institut National de la Santé et de la Recherche Médicale, Centre National de la Recherche Scientifique, Institut de la Vision, Paris F-75012, France
| | - Christian Boehler
- Department of Microsystems Engineering (IMTEK), University of Freiburg, Georges-Köhler-Allee 103, 79110 Freiburg, Germany
- BrainLinks-BrainTools Center, University of Freiburg, Georges-Köhler-Allee 201, 79110 Freiburg, Germany
| | - Maria Asplund
- Department of Microsystems Engineering (IMTEK), University of Freiburg, Georges-Köhler-Allee 103, 79110 Freiburg, Germany
- BrainLinks-BrainTools Center, University of Freiburg, Georges-Köhler-Allee 201, 79110 Freiburg, Germany
- Freiburg Institute for Advanced Studies (FRIAS), University of Freiburg, Albertstraße 19, 79104 Freiburg, Germany
- Chalmers University of Technology, Chalmersplatsen 4, 412 96 Gothenburg, Sweden
| | - Pieter Roelf Roelfsema
- Department of Vision and Cognition, Netherlands Institute for Neuroscience, Meibergdreef 47, 1105 BA Amsterdam, The Netherlands
- Laboratory of Visual Brain Therapy, Sorbonne Université, Institut National de la Santé et de la Recherche Médicale, Centre National de la Recherche Scientifique, Institut de la Vision, Paris F-75012, France
- Department of Integrative Neurophysiology, VU University, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands
- Department of Psychiatry, Academic Medical Center, Postbus 22660, 1100 DD Amsterdam, The Netherlands
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Abstract
Soft robotics facilitates the deployment of large radial electrode arrays on the brain cortex through small craniotomies.
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Affiliation(s)
- Maria Asplund
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, Gothenburg, Sweden
- Department of Health, Education and Technology, Luleå University of Technology, Luleå, Sweden
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Böhler C, Vomero M, Soula M, Vöröslakos M, Porto Cruz M, Liljemalm R, Buzsaki G, Stieglitz T, Asplund M. Multilayer Arrays for Neurotechnology Applications (MANTA): Chronically Stable Thin-Film Intracortical Implants. Adv Sci (Weinh) 2023; 10:e2207576. [PMID: 36935361 DOI: 10.1002/advs.202207576] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 02/07/2023] [Indexed: 05/18/2023]
Abstract
Flexible implantable neurointerfaces show great promise in addressing one of the major challenges of implantable neurotechnology, namely the loss of signal connected to unfavorable probe tissue interaction. The authors here show how multilayer polyimide probes allow high-density intracortical recordings to be combined with a reliable long-term stable tissue interface, thereby progressing toward chronic stability of implantable neurotechnology. The probes could record 10-60 single units over 5 months with a consistent peak-to-peak voltage at dimensions that ensure robust handling and insulation longevity. Probes that remain in intimate contact with the signaling tissue over months to years are a game changer for neuroscience and, importantly, open up for broader clinical translation of systems relying on neurotechnology to interface the human brain.
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Affiliation(s)
- Christian Böhler
- Department of Microsystems Engineering (IMTEK), University of Freiburg, 79110, Freiburg, Germany
- BrainLinks-BrainTools Center, University of Freiburg, 79110, Freiburg, Germany
| | - Maria Vomero
- Department of Microsystems Engineering (IMTEK), University of Freiburg, 79110, Freiburg, Germany
- BrainLinks-BrainTools Center, University of Freiburg, 79110, Freiburg, Germany
| | - Marisol Soula
- Neuroscience Institute, Langone Medical Center, New York University, New York, 10016, USA
| | - Mihály Vöröslakos
- Neuroscience Institute, Langone Medical Center, New York University, New York, 10016, USA
| | - Maria Porto Cruz
- Department of Microsystems Engineering (IMTEK), University of Freiburg, 79110, Freiburg, Germany
- BrainLinks-BrainTools Center, University of Freiburg, 79110, Freiburg, Germany
| | - Rickard Liljemalm
- Department of Microsystems Engineering (IMTEK), University of Freiburg, 79110, Freiburg, Germany
| | - György Buzsaki
- Neuroscience Institute, Langone Medical Center, New York University, New York, 10016, USA
- Department of Physiology and Neuroscience, Langone Medical Center, New York University, New York, 10016, USA
- Department of Neurology, Langone Medical Center, New York University, New York, 10016, USA
| | - Thomas Stieglitz
- Department of Microsystems Engineering (IMTEK), University of Freiburg, 79110, Freiburg, Germany
- BrainLinks-BrainTools Center, University of Freiburg, 79110, Freiburg, Germany
- Bernstein Center Freiburg, University of Freiburg, 79110, Freiburg, Germany
| | - Maria Asplund
- Department of Microsystems Engineering (IMTEK), University of Freiburg, 79110, Freiburg, Germany
- BrainLinks-BrainTools Center, University of Freiburg, 79110, Freiburg, Germany
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, Gothenburg, SE-41296, Sweden
- Division of Nursing and Medical Technology, Luleå University of Technology, Luleå, 97187, Sweden
- Freiburg Institute for Advanced Studies (FRIAS), University of Freiburg, 79110, Freiburg, Germany
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12
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Shaner S, Savelyeva A, Kvartuh A, Jedrusik N, Matter L, Leal J, Asplund M. Bioelectronic microfluidic wound healing: a platform for investigating direct current stimulation of injured cell collectives. Lab Chip 2023; 23:1531-1546. [PMID: 36723025 PMCID: PMC10013350 DOI: 10.1039/d2lc01045c] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Accepted: 01/14/2023] [Indexed: 06/18/2023]
Abstract
Upon cutaneous injury, the human body naturally forms an electric field (EF) that acts as a guidance cue for relevant cellular and tissue repair and reorganization. However, the direct current (DC) flow imparted by this EF can be impacted by a variety of diseases. This work delves into the impact of DC stimulation on both healthy and diabetic in vitro wound healing models of human keratinocytes, the most prevalent cell type of the skin. The culmination of non-metal electrode materials and prudent microfluidic design allowed us to create a compact bioelectronic platform to study the effects of different sustained (12 hours galvanostatic DC) EF configurations on wound closure dynamics. Specifically, we compared if electrotactically closing a wound's gap from one wound edge (i.e., uni-directional EF) is as effective as compared to alternatingly polarizing both the wound's edges (i.e., pseudo-converging EF) as both of these spatial stimulation strategies are fundamental to the eventual translational electrode design and strategy. We found that uni-directional electric guidance cues were superior in group keratinocyte healing dynamics by enhancing the wound closure rate nearly three-fold for both healthy and diabetic-like keratinocyte collectives, compared to their non-stimulated respective controls. The motility-inhibited and diabetic-like keratinocytes regained wound closure rates with uni-directional electrical stimulation (increase from 1.0 to 2.8% h-1) comparable to their healthy non-stimulated keratinocyte counterparts (3.5% h-1). Our results bring hope that electrical stimulation delivered in a controlled manner can be a viable pathway to accelerate wound repair, and also by providing a baseline for other researchers trying to find an optimal electrode blueprint for in vivo DC stimulation.
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Affiliation(s)
- Sebastian Shaner
- Department of Microsystems Engineering, University of Freiburg, Georges-Köhler-Allee 201, 79110, Freiburg, Germany
- Brainlinks-Braintools Center, Georges-Köhler-Allee 201, 79110, Freiburg, Germany.
| | - Anna Savelyeva
- Department of Microsystems Engineering, University of Freiburg, Georges-Köhler-Allee 201, 79110, Freiburg, Germany
- Brainlinks-Braintools Center, Georges-Köhler-Allee 201, 79110, Freiburg, Germany.
| | - Anja Kvartuh
- Department of Microsystems Engineering, University of Freiburg, Georges-Köhler-Allee 201, 79110, Freiburg, Germany
| | - Nicole Jedrusik
- Department of Microsystems Engineering, University of Freiburg, Georges-Köhler-Allee 201, 79110, Freiburg, Germany
- Brainlinks-Braintools Center, Georges-Köhler-Allee 201, 79110, Freiburg, Germany.
| | - Lukas Matter
- Department of Microsystems Engineering, University of Freiburg, Georges-Köhler-Allee 201, 79110, Freiburg, Germany
| | - José Leal
- Department of Microsystems Engineering, University of Freiburg, Georges-Köhler-Allee 201, 79110, Freiburg, Germany
- Brainlinks-Braintools Center, Georges-Köhler-Allee 201, 79110, Freiburg, Germany.
| | - Maria Asplund
- Department of Microsystems Engineering, University of Freiburg, Georges-Köhler-Allee 201, 79110, Freiburg, Germany
- Brainlinks-Braintools Center, Georges-Köhler-Allee 201, 79110, Freiburg, Germany.
- Freiburg Institute for Advanced Studies (FRIAS), University of Freiburg, Albertstr. 19, 79104, Freiburg, Germany
- Division of Nursing and Medical Technology, Luleå University of Technology, 971 87, Luleå, Sweden
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, Kemivägen 9, 412 58, Gothenburg, Sweden.
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13
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Harland B, Aqrawe Z, Vomero M, Boehler C, Cheah E, Raos B, Asplund M, O'Carroll SJ, Svirskis D. A Subdural Bioelectronic Implant to Record Electrical Activity from the Spinal Cord in Freely Moving Rats. Adv Sci (Weinh) 2022; 9:e2105913. [PMID: 35499184 PMCID: PMC9284137 DOI: 10.1002/advs.202105913] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 04/06/2022] [Indexed: 05/28/2023]
Abstract
Bioelectronic devices have found use at the interface with neural tissue to investigate and treat nervous system disorders. Here, the development and characterization of a very thin flexible bioelectronic implant inserted along the thoracic spinal cord in rats directly in contact with and conformable to the dorsal surface of the spinal cord are presented. There is no negative impact on hind-limb functionality nor any change in the volume or shape of the spinal cord. The bioelectronic implant is maintained in rats for a period of 12 weeks. The first subdural recordings of spinal cord activity in freely moving animals are presented; rats are plugged in via a recording cable and allowed to freely behave and move around on a raised platform. Recordings contained multiple distinct voltage waveforms spatially localize to individual electrodes. This device has great potential to monitor electrical signaling in the spinal cord after an injury and in the future, this implant will facilitate the identification of biomarkers in spinal cord injury and recovery, while enabling the delivery of localized electroceutical and chemical treatments.
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Affiliation(s)
- Bruce Harland
- School of PharmacyThe University of AucklandAuckland1023New Zealand
| | - Zaid Aqrawe
- School of PharmacyThe University of AucklandAuckland1023New Zealand
| | - Maria Vomero
- Department of Microsystems Engineering (IMTEK)BrainLinks‐BrainTools CenterUniversity of FreiburgFreiburg79110Germany
| | - Christian Boehler
- Department of Microsystems Engineering (IMTEK)BrainLinks‐BrainTools CenterUniversity of FreiburgFreiburg79110Germany
| | - Ernest Cheah
- School of PharmacyThe University of AucklandAuckland1023New Zealand
| | - Brad Raos
- School of PharmacyThe University of AucklandAuckland1023New Zealand
| | - Maria Asplund
- Department of Microsystems Engineering (IMTEK)BrainLinks‐BrainTools Center and Freiburg Institute for Advanced Studies (FRIAS)University of FreiburgFreiburg79110Germany
- Division of Nursing and Medical TechnologyLuleå University of TechnologyLuleå971 87Sweden
| | - Simon J. O'Carroll
- Department of Anatomy & Medical ImagingSchool of Medical SciencesThe University of AucklandAuckland1023New Zealand
| | - Darren Svirskis
- School of PharmacyThe University of AucklandAuckland1023New Zealand
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14
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Bianchi M, De Salvo A, Asplund M, Carli S, Di Lauro M, Schulze‐Bonhage A, Stieglitz T, Fadiga L, Biscarini F. Poly(3,4-ethylenedioxythiophene)-Based Neural Interfaces for Recording and Stimulation: Fundamental Aspects and In Vivo Applications. Adv Sci (Weinh) 2022; 9:e2104701. [PMID: 35191224 PMCID: PMC9036021 DOI: 10.1002/advs.202104701] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Revised: 01/04/2022] [Indexed: 05/29/2023]
Abstract
Next-generation neural interfaces for bidirectional communication with the central nervous system aim to achieve the intimate integration with the neural tissue with minimal neuroinflammatory response, high spatio-temporal resolution, very high sensitivity, and readout stability. The design and manufacturing of devices for low power/low noise neural recording and safe and energy-efficient stimulation that are, at the same time, conformable to the brain, with matched mechanical properties and biocompatibility, is a convergence area of research where neuroscientists, materials scientists, and nanotechnologists operate synergically. The biotic-abiotic neural interface, however, remains a formidable challenge that prompts for new materials platforms and innovation in device layouts. Conductive polymers (CP) are attractive materials to be interfaced with the neural tissue and to be used as sensing/stimulating electrodes because of their mixed ionic-electronic conductivity, their low contact impedance, high charge storage capacitance, chemical versatility, and biocompatibility. This manuscript reviews the state-of-the-art of poly(3,4-ethylenedioxythiophene)-based neural interfaces for extracellular recording and stimulation, focusing on those technological approaches that are successfully demonstrated in vivo. The aim is to highlight the most reliable and ready-for-clinical-use solutions, in terms of materials technology and recording performance, other than spot major limitations and identify future trends in this field.
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Affiliation(s)
- Michele Bianchi
- Center for Translational Neurophysiology of Speech and CommunicationFondazione Istituto Italiano di Tecnologiavia Fossato di Mortara 17Ferrara44121Italy
| | - Anna De Salvo
- Center for Translational Neurophysiology of Speech and CommunicationFondazione Istituto Italiano di Tecnologiavia Fossato di Mortara 17Ferrara44121Italy
- Sezione di FisiologiaUniversità di Ferraravia Fossato di Mortara 17Ferrara44121Italy
| | - Maria Asplund
- Division of Nursing and Medical TechnologyLuleå University of TechnologyLuleå971 87Sweden
- Department of Microsystems Engineering‐IMTEKUniversity of FreiburgFreiburg79110Germany
- BrainLinks‐BrainTools CenterUniversity of FreiburgFreiburg79110Germany
| | - Stefano Carli
- Center for Translational Neurophysiology of Speech and CommunicationFondazione Istituto Italiano di Tecnologiavia Fossato di Mortara 17Ferrara44121Italy
- Present address:
Department of Environmental and Prevention SciencesUniversità di FerraraFerrara44121Italy
| | - Michele Di Lauro
- Center for Translational Neurophysiology of Speech and CommunicationFondazione Istituto Italiano di Tecnologiavia Fossato di Mortara 17Ferrara44121Italy
| | - Andreas Schulze‐Bonhage
- BrainLinks‐BrainTools CenterUniversity of FreiburgFreiburg79110Germany
- Epilepsy CenterFaculty of MedicineUniversity of FreiburgFreiburg79110Germany
| | - Thomas Stieglitz
- Department of Microsystems Engineering‐IMTEKUniversity of FreiburgFreiburg79110Germany
- BrainLinks‐BrainTools CenterUniversity of FreiburgFreiburg79110Germany
| | - Luciano Fadiga
- Center for Translational Neurophysiology of Speech and CommunicationFondazione Istituto Italiano di Tecnologiavia Fossato di Mortara 17Ferrara44121Italy
- Sezione di FisiologiaUniversità di Ferraravia Fossato di Mortara 17Ferrara44121Italy
| | - Fabio Biscarini
- Center for Translational Neurophysiology of Speech and CommunicationFondazione Istituto Italiano di Tecnologiavia Fossato di Mortara 17Ferrara44121Italy
- Life Science DepartmentUniversità di Modena e Reggio EmiliaVia Campi 103Modena41125Italy
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15
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Barnes CJ, Clausen ML, Asplund M, Rasmussen L, Olesen CM, Yüsel YT, Andersen PS, Litman T, Hansen AJ, Agner T. Temporal and Spatial Variation of the Skin-Associated Bacteria from Healthy Participants and Atopic Dermatitis Patients. mSphere 2022; 7:e0091721. [PMID: 35196118 PMCID: PMC8865923 DOI: 10.1128/msphere.00917-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Accepted: 01/21/2022] [Indexed: 12/22/2022] Open
Abstract
Several factors have been shown to influence the composition of the bacterial communities inhabiting healthy skin, with variation between different individuals, differing skin depths, and body locations (spatial-temporal variation). Atopic dermatitis (AD) is a chronic skin disease also affecting the skin-associated bacterial communities. While the effects of AD have been studied on these processes individually, few have considered how AD disrupts the spatial-temporal variation of the skin bacteria as a whole (i.e., considered these processes simultaneously). Here, we characterized the skin-associated bacterial communities of healthy volunteers and lesional and nonlesional skin of AD patients by metabarcoding the universal V3-V4 16S rRNA region from tape strip skin samples. We quantified the spatial-temporal variation (interindividual variation, differing skin depths, multiple time points) of the skin-associated bacteria within healthy controls and AD patients, including the relative change induced by AD in each. Interindividual variation correlated with the bacterial community far more strongly than any other factors followed by skin depth and then AD status. There was no significant temporal variation found within either AD patients or healthy controls. The bacterial community was found to vary markedly according to AD severity, and between patients without and with filaggrin mutations. Therefore, future studies may benefit from sampling subsurface epidermal communities and considering AD severity and the host genome in understanding the role of the skin bacterial community within AD pathogenesis rather than considering AD as a presence-absence disorder. IMPORTANCE The bacteria associated with human skin may influence skin barrier function and the immune response. Previous studies have attempted to understand the factors that regulate the skin bacteria, characterizing the spatial-temporal variation of the skin bacteria within unaffected skin. Here, we quantified the effect of AD on the skin bacteria on multiple spatial-temporal factors simultaneously. Although significant community variation between healthy controls and AD patients was observed, the effects of AD on the overall bacterial community were relatively low compared to other measured factors. Results here suggest that changes in specific taxa rather than wholesale changes in the skin bacteria are associated with mild to moderate AD. Further studies would benefit from incorporating the complexity of AD into models to better understand the condition, including AD severity and the host genome, alongside microbial composition.
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Affiliation(s)
- Christopher J. Barnes
- The Globe Institute, Faculty of Health, University of Copenhagen, Copenhagen, Denmark
| | - Maja-Lisa Clausen
- Department of Dermatology, Bispebjerg Hospital, University of Copenhagen, Copenhagen, Denmark
| | - Maria Asplund
- The Globe Institute, Faculty of Health, University of Copenhagen, Copenhagen, Denmark
| | - Linett Rasmussen
- The Globe Institute, Faculty of Health, University of Copenhagen, Copenhagen, Denmark
| | - Caroline Meyer Olesen
- Department of Dermatology, Bispebjerg Hospital, University of Copenhagen, Copenhagen, Denmark
| | - Yasemin Topal Yüsel
- Department of Dermatology, Bispebjerg Hospital, University of Copenhagen, Copenhagen, Denmark
| | - Paal Skytt Andersen
- Department of Bacteria, Parasites and Fungi, Statens Serum Insitute, Copenhagen, Denmark
| | - Thomas Litman
- Department of Immunology and Microbiology, LEO Foundation Skin Immunology Research Center, University of Copenhagen, Copenhagen, Denmark
| | | | - Tove Agner
- Department of Dermatology, Bispebjerg Hospital, University of Copenhagen, Copenhagen, Denmark
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16
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Vomero M, Ciarpella F, Zucchini E, Kirsch M, Fadiga L, Stieglitz T, Asplund M. On the longevity of flexible neural interfaces: Establishing biostability of polyimide-based intracortical implants. Biomaterials 2022; 281:121372. [DOI: 10.1016/j.biomaterials.2022.121372] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Revised: 12/27/2021] [Accepted: 01/10/2022] [Indexed: 11/02/2022]
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17
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Otte E, Vlachos A, Asplund M. Engineering strategies towards overcoming bleeding and glial scar formation around neural probes. Cell Tissue Res 2022; 387:461-477. [PMID: 35029757 PMCID: PMC8975777 DOI: 10.1007/s00441-021-03567-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Accepted: 12/17/2021] [Indexed: 12/15/2022]
Abstract
Neural probes are sophisticated electrophysiological tools used for intra-cortical recording and stimulation. These microelectrode arrays, designed to penetrate and interface the brain from within, contribute at the forefront of basic and clinical neuroscience. However, one of the challenges and currently most significant limitations is their ‘seamless’ long-term integration into the surrounding brain tissue. Following implantation, which is typically accompanied by bleeding, the tissue responds with a scarring process, resulting in a gliotic region closest to the probe. This glial scarring is often associated with neuroinflammation, neurodegeneration, and a leaky blood–brain interface (BBI). The engineering progress on minimizing this reaction in the form of improved materials, microfabrication, and surgical techniques is summarized in this review. As research over the past decade has progressed towards a more detailed understanding of the nature of this biological response, it is time to pose the question: Are penetrating probes completely free from glial scarring at all possible?
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18
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Maoz BM, Asplund M, Maggio N, Vlachos A. Technology-based approaches toward a better understanding of neuro-coagulation in brain homeostasis. Cell Tissue Res 2021; 387:493-498. [PMID: 34850274 PMCID: PMC8975761 DOI: 10.1007/s00441-021-03560-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Accepted: 11/12/2021] [Indexed: 12/30/2022]
Abstract
Blood coagulation factors can enter the brain under pathological conditions that affect the blood–brain interface. Besides their contribution to pathological brain states, such as neural hyperexcitability, neurodegeneration, and scar formation, coagulation factors have been linked to several physiological brain functions. It is for example well established that the coagulation factor thrombin modulates synaptic plasticity; it affects neural excitability and induces epileptic seizures via activation of protease-activated receptors in the brain. However, major limitations of current experimental and clinical approaches have prevented us from obtaining a profound mechanistic understanding of “neuro-coagulation” in health and disease. Here, we present how novel human relevant models, i.e., Organ-on-Chips equipped with advanced sensors, can help overcoming some of the limitations in the field, thus providing a perspective toward a better understanding of neuro-coagulation in brain homeostasis.
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Affiliation(s)
- Ben M Maoz
- Department of Biomedical Engineering, Tel Aviv University, Tel Aviv, Israel.,Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel.,The Center for Nanoscience and Nanotechnology, Tel Aviv University, Tel Aviv, Israel
| | - Maria Asplund
- Department of Microsystems Engineering (IMTEK), University of Freiburg, Freiburg, Germany.,Center BrainLinks-BrainTools, University of Freiburg, Freiburg, Germany.,Division of Nursing and Medical Technology, Luleå University of Technology, Lulea, Sweden
| | - Nicola Maggio
- Department of Neurology, The Chaim Sheba Medical Center, Tel Hashomer, Israel.,Department of Neurology and Neurosurgery, Sackler Faculty of Medicine and Sagol School of Neuroscience, Tel Aviv University, Israel
| | - Andreas Vlachos
- Center BrainLinks-BrainTools, University of Freiburg, Freiburg, Germany. .,Department of Neuroanatomy, Institute of Anatomy and Cell Biology, Faculty of Medicine, University of Freiburg, Freiburg, Germany. .,Center for Basics in Neuromodulation (NeuroModulBasics), Faculty of Medicine, University of Freiburg, Freiburg, Germany.
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19
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Boehler C, Carli S, Fadiga L, Stieglitz T, Asplund M. Tutorial: guidelines for standardized performance tests for electrodes intended for neural interfaces and bioelectronics. Nat Protoc 2020; 15:3557-3578. [DOI: 10.1038/s41596-020-0389-2] [Citation(s) in RCA: 61] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Accepted: 07/28/2020] [Indexed: 01/22/2023]
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20
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Barnes CJ, Rasmussen L, Asplund M, Knudsen SW, Clausen ML, Agner T, Hansen AJ. Comparing DADA2 and OTU clustering approaches in studying the bacterial communities of atopic dermatitis. J Med Microbiol 2020; 69:1293-1302. [PMID: 32965212 PMCID: PMC7717693 DOI: 10.1099/jmm.0.001256] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Introduction The pathogenesis of atopic dermatitis (AD) is not yet fully understood, but the bacterial composition of AD patients’ skin has been shown to have an increased abundance of Staphylococcus aureus. More recently, coagulase-negative Staphylococcus (CoNS) species were shown to be able to inhibit S. aureus, but further studies are required to determine the effects of Staphylococcus community variation in AD. Aim Here we investigated whether analysing metabarcoding data with the more recently developed DADA2 approach improves metabarcoding analyses compared to the previously used operational taxonomic unit (OTU) clustering, and can be used to study Staphylococcus community dynamics. Methods The bacterial 16S rRNA region from tape strip samples of the stratum corneum of AD patients (non-lesional skin) and non-AD controls was metabarcoded. We processed metabarcoding data with two different bioinformatic pipelines (an OTU clustering method and DADA2), which were analysed with and without technical replication (sampling strategy). Results We found that OTU clustering and DADA2 performed well for community-level studies, as demonstrated by the identification of significant differences in the skin bacterial communities associated with AD. However, the OTU clustering approach inflated bacterial richness, which was worsened by not having technical replication. Data processed with DADA2 likely handled sequencing errors more effectively and thereby did not inflate molecular richness. Conclusion We believe that DADA2 represents an improvement over an OTU clustering approach, and that biological replication rather than technical replication is a more effective use of resources. However, neither OTU clustering nor DADA2 gave insights into Staphylococcus community dynamics, and caution should remain in not overinterpreting the taxonomic assignments at lower taxonomic ranks.
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Affiliation(s)
- Christopher J Barnes
- Natural History Museum of Denmark, Department of Biology, University of Copenhagen, Denmark.,The Globe Institute, Faculty of Health, University of Copenhagen, Denmark
| | - Linett Rasmussen
- The Globe Institute, Faculty of Health, University of Copenhagen, Denmark
| | - Maria Asplund
- The Globe Institute, Faculty of Health, University of Copenhagen, Denmark
| | | | - Maja-Lisa Clausen
- Department of Dermatology, Bispebjerg Hospital, University of Copenhagen, Denmark
| | - Tove Agner
- Department of Dermatology, Bispebjerg Hospital, University of Copenhagen, Denmark
| | - Anders J Hansen
- The Globe Institute, Faculty of Health, University of Copenhagen, Denmark
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21
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Mollerup S, Asplund M, Friis-Nielsen J, Kjartansdóttir KR, Fridholm H, Hansen TA, Herrera JAR, Barnes CJ, Jensen RH, Richter SR, Nielsen IB, Pietroni C, Alquezar-Planas DE, Rey-Iglesia A, Olsen PVS, Rajpert-De Meyts E, Groth-Pedersen L, von Buchwald C, Jensen DH, Gniadecki R, Høgdall E, Langhoff JL, Pete I, Vereczkey I, Baranyai Z, Dybkaer K, Johnsen HE, Steiniche T, Hokland P, Rosenberg J, Baandrup U, Sicheritz-Pontén T, Willerslev E, Brunak S, Lund O, Mourier T, Vinner L, Izarzugaza JMG, Nielsen LP, Hansen AJ. High-Throughput Sequencing-Based Investigation of Viruses in Human Cancers by Multienrichment Approach. J Infect Dis 2020; 220:1312-1324. [PMID: 31253993 PMCID: PMC6743825 DOI: 10.1093/infdis/jiz318] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2019] [Accepted: 06/27/2019] [Indexed: 01/10/2023] Open
Abstract
Background Viruses and other infectious agents cause more than 15% of human cancer cases. High-throughput sequencing-based studies of virus-cancer associations have mainly focused on cancer transcriptome data. Methods In this study, we applied a diverse selection of presequencing enrichment methods targeting all major viral groups, to characterize the viruses present in 197 samples from 18 sample types of cancerous origin. Using high-throughput sequencing, we generated 710 datasets constituting 57 billion sequencing reads. Results Detailed in silico investigation of the viral content, including exclusion of viral artefacts, from de novo assembled contigs and individual sequencing reads yielded a map of the viruses detected. Our data reveal a virome dominated by papillomaviruses, anelloviruses, herpesviruses, and parvoviruses. More than half of the included samples contained 1 or more viruses; however, no link between specific viruses and cancer types were found. Conclusions Our study sheds light on viral presence in cancers and provides highly relevant virome data for future reference.
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Affiliation(s)
- Sarah Mollerup
- Centre for GeoGenetics, Natural History Museum of Denmark, University of Copenhagen, Denmark
| | - Maria Asplund
- Centre for GeoGenetics, Natural History Museum of Denmark, University of Copenhagen, Denmark
| | - Jens Friis-Nielsen
- Department of Bio and Health Informatics, Technical University of Denmark, Lyngby, Denmark
| | | | - Helena Fridholm
- Centre for GeoGenetics, Natural History Museum of Denmark, University of Copenhagen, Denmark
| | - Thomas Arn Hansen
- Centre for GeoGenetics, Natural History Museum of Denmark, University of Copenhagen, Denmark
| | - José Alejandro Romero Herrera
- Department of Bio and Health Informatics, Technical University of Denmark, Lyngby, Denmark.,Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
| | | | - Randi Holm Jensen
- Centre for GeoGenetics, Natural History Museum of Denmark, University of Copenhagen, Denmark
| | - Stine Raith Richter
- Centre for GeoGenetics, Natural History Museum of Denmark, University of Copenhagen, Denmark
| | - Ida Broman Nielsen
- Centre for GeoGenetics, Natural History Museum of Denmark, University of Copenhagen, Denmark
| | - Carlotta Pietroni
- Centre for GeoGenetics, Natural History Museum of Denmark, University of Copenhagen, Denmark
| | - David E Alquezar-Planas
- Centre for GeoGenetics, Natural History Museum of Denmark, University of Copenhagen, Denmark
| | - Alba Rey-Iglesia
- Centre for GeoGenetics, Natural History Museum of Denmark, University of Copenhagen, Denmark
| | - Pernille V S Olsen
- Centre for GeoGenetics, Natural History Museum of Denmark, University of Copenhagen, Denmark
| | - Ewa Rajpert-De Meyts
- Department of Growth and Reproduction, Copenhagen University Hospital (Rigshospitalet), Denmark
| | - Line Groth-Pedersen
- Department of Pediatrics and Adolescent Medicine, University Hospital Rigshospitalet, Denmark
| | - Christian von Buchwald
- Department of Otorhinolaryngology, Head and Neck Surgery and Audiology, Rigshospitalet, Copenhagen University Hospital
| | - David H Jensen
- Department of Otorhinolaryngology, Head and Neck Surgery and Audiology, Rigshospitalet, Copenhagen University Hospital
| | - Robert Gniadecki
- Department of Dermato-Venerology, Faculty of Health Sciences, Copenhagen University Hospital, Bispebjerg Hospital, Denmark
| | - Estrid Høgdall
- Department of Pathology, Herlev and Gentofte Hospital, University of Copenhagen, Denmark
| | - Jill Levin Langhoff
- Department of Pathology, Herlev and Gentofte Hospital, University of Copenhagen, Denmark
| | - Imre Pete
- National Institute of Oncology, Department of Gynecology, Budapest, Hungary
| | - Ildikó Vereczkey
- National Institute of Oncology, Department of Gynecology, Budapest, Hungary
| | - Zsolt Baranyai
- 1st Department of Surgery, Semmelweis University, Budapest, Hungary
| | - Karen Dybkaer
- Department of Clinical Medicine, Aalborg University, Denmark
| | | | | | - Peter Hokland
- Department of Clinical Medicine, Department of Haematology, Aarhus University Hospital, Denmark
| | - Jacob Rosenberg
- Department of Surgery, Herlev and Gentofte Hospital, University of Copenhagen, Denmark
| | - Ulrik Baandrup
- Center for Clinical Research, North Denmark Regional Hospital and Department of Clinical Medicine, Aalborg University, Hjørring, Denmark
| | - Thomas Sicheritz-Pontén
- Department of Bio and Health Informatics, Technical University of Denmark, Lyngby, Denmark.,Centre of Excellence for Omics-Driven Computational Biodiscovery, AIMST University, Kedah, Malaysia
| | - Eske Willerslev
- Centre for GeoGenetics, Natural History Museum of Denmark, University of Copenhagen, Denmark
| | - Søren Brunak
- Department of Bio and Health Informatics, Technical University of Denmark, Lyngby, Denmark.,Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
| | - Ole Lund
- Department of Bio and Health Informatics, Technical University of Denmark, Lyngby, Denmark
| | - Tobias Mourier
- Centre for GeoGenetics, Natural History Museum of Denmark, University of Copenhagen, Denmark
| | - Lasse Vinner
- Centre for GeoGenetics, Natural History Museum of Denmark, University of Copenhagen, Denmark
| | - Jose M G Izarzugaza
- Department of Bio and Health Informatics, Technical University of Denmark, Lyngby, Denmark
| | - Lars Peter Nielsen
- Department of Autoimmunology and Biomarkers, Statens Serum Institut, Copenhagen S, Denmark
| | - Anders Johannes Hansen
- Centre for GeoGenetics, Natural History Museum of Denmark, University of Copenhagen, Denmark
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22
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Boehler C, Vieira DM, Egert U, Asplund M. NanoPt-A Nanostructured Electrode Coating for Neural Recording and Microstimulation. ACS Appl Mater Interfaces 2020; 12:14855-14865. [PMID: 32162910 DOI: 10.1021/acsami.9b22798] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Bioelectronic devices, interfacing neural tissue for therapeutic, diagnostic, or rehabilitation purposes, rely on small electrode contacts in order to achieve highly sophisticated communication at the neural interface. Reliable recording and safe stimulation with small electrodes, however, are limited when conventional electrode metallizations are used, demanding the development of new materials to enable future progress within bioelectronics. In this study, we present a versatile process for the realization of nanostructured platinum (nanoPt) coatings with a high electrochemically active surface area, showing promising biocompatibility and providing low impedance, high charge injection capacity, and outstanding long-term stability both for recording and stimulation. The proposed electrochemical fabrication process offers exceptional control over the nanoPt deposition, allowing the realization of specific coating morphologies such as small grains, pyramids, or nanoflakes, and can moreover be scaled up to wafer level or batch fabrication under economic process conditions. The suitability of nanoPt as a coating for neural interfaces is here demonstrated, in vitro and in vivo, revealing superior stimulation performance under chronic conditions. Thus, nanoPt offers promising qualities as an advanced neural interface coating which moreover extends to the numerous application fields where a large (electro)chemically active surface area contributes to increased efficiency.
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Affiliation(s)
- Christian Boehler
- Department of Microsystems Engineering (IMTEK)-ElectroActive Coatings Group, University of Freiburg, Georges-Koehler-Allee 102, 79110 Freiburg, Germany
- BrainLinks-BrainTools Center, University of Freiburg, 79110 Freiburg, Germany
| | - Diego M Vieira
- BrainLinks-BrainTools Center, University of Freiburg, 79110 Freiburg, Germany
- Department of Microsystems Engineering (IMTEK)-Laboratory for Biomicrotechnology, University of Freiburg, Georges-Koehler-Allee 102, 79110 Freiburg, Germany
- Bernstein Center Freiburg (BCF), University of Freiburg, 79110 Freiburg, Germany
| | - Ulrich Egert
- BrainLinks-BrainTools Center, University of Freiburg, 79110 Freiburg, Germany
- Department of Microsystems Engineering (IMTEK)-Laboratory for Biomicrotechnology, University of Freiburg, Georges-Koehler-Allee 102, 79110 Freiburg, Germany
- Bernstein Center Freiburg (BCF), University of Freiburg, 79110 Freiburg, Germany
| | - Maria Asplund
- Department of Microsystems Engineering (IMTEK)-ElectroActive Coatings Group, University of Freiburg, Georges-Koehler-Allee 102, 79110 Freiburg, Germany
- BrainLinks-BrainTools Center, University of Freiburg, 79110 Freiburg, Germany
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23
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Abstract
As scientists and engineers, we must recognize the overwhelming evidence that we each harbor bias that influences our professional decisions. Yet, solving today's increasingly complex public health challenges requires diverse perspectives from multidisciplinary teams. We all have the opportunity to actively promote a more representative scientific community; let's harness the power of collective action to build diverse teams that deliver the most innovative science.
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Affiliation(s)
- Maria Asplund
- BrainLinks-BrainTools Center, University of Freiburg, Freiburg, Germany; Department of Microsystems Engineering (IMTEK), University of Freiburg, Freiburg, Germany.
| | - Cristin G Welle
- Departments of Neurosurgery and Bioengineering, University of Colorado-Anschutz Medical Campus, Aurora, CO, USA.
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24
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Kleber C, Lienkamp K, Rühe J, Asplund M. Wafer-Scale Fabrication of Conducting Polymer Hydrogels for Microelectrodes and Flexible Bioelectronics. ACTA ACUST UNITED AC 2019; 3:e1900072. [PMID: 32648703 DOI: 10.1002/adbi.201900072] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 06/13/2019] [Indexed: 11/06/2022]
Abstract
Future-oriented directions in neural interface technologies point towards the development of multimodal devices that combine different functionalities such as neural stimulation, neurotransmitter sensing, and drug release within one platform. Conducting polymer hydrogels (CPHs) are suggested as materials for the coating of standard metal electrodes to add functionalities such as local delivery of therapeutic drugs. However, to make such coatings truly useful for multimodal devices, it is necessary to develop process technologies that allow the micropatterning of CPHs onto selected electrode sites. In this study, a wafer-scale fabrication procedure is presented, which is used to coat the CPH, based on the hydrogel P(DMAA-co-5%MABP-co-2,5%SSNa) and the conducting polymer poly(3,4-ethylenedioxythiophene) (PEDOT), onto flexible neural probes. The resulting material has favorable properties for the generation of recording electrodes and in addition offers a convenient platform for biofunctionalization. By controlling the PEDOT content within the hydrogel matrix, charge injection limits of up to 3.7 mC cm- 2 are obtained. Long-term stability is tested by immersing coated samples in phosphate-buffered saline solution at 37 °C for 1 year. Non-cytotoxicity of the coatings is confirmed with a direct cell culture test using a fluorescent neuroblastoma cell line.
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Affiliation(s)
- Carolin Kleber
- Department of Microsystems Engineering, IMTEK, University of Freiburg, 79110, Freiburg, Germany.,Brainlinks-Braintools, University of Freiburg, 79110, Freiburg, Germany
| | - Karen Lienkamp
- Department of Microsystems Engineering, IMTEK, University of Freiburg, 79110, Freiburg, Germany.,FIT - Freiburg Centre for Interactive Materials and Bioinspired Technologies, University of Freiburg, 79110, Freiburg, Germany
| | - Jürgen Rühe
- Department of Microsystems Engineering, IMTEK, University of Freiburg, 79110, Freiburg, Germany.,Brainlinks-Braintools, University of Freiburg, 79110, Freiburg, Germany.,FIT - Freiburg Centre for Interactive Materials and Bioinspired Technologies, University of Freiburg, 79110, Freiburg, Germany
| | - Maria Asplund
- Department of Microsystems Engineering, IMTEK, University of Freiburg, 79110, Freiburg, Germany.,Brainlinks-Braintools, University of Freiburg, 79110, Freiburg, Germany
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25
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Abstract
The widespread use of conducting polymers, especially poly(3,4-ethylene dioxythiophene) (PEDOT), within the space of bioelectronics has enabled improvements, both in terms of electrochemistry and functional versatility, of conventional metallic electrodes. This short review aims to provide an overview of how PEDOT coatings have contributed to functionalizing existing bioelectronics, the challenges which meet conducting polymer coatings from a regulatory and stability point of view and the possibilities to bring PEDOT-based coatings into large-scale clinical applications. Finally, their potential use for enabling new technologies for the field of bioelectronics as biodegradable, stretchable and slow-stimulation materials will be discussed.
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Affiliation(s)
- Christian Boehler
- BrainLinks-BrainTools Center, University of Freiburg, Freiburg, Germany
- Department of Microsystems Engineering (IMTEK), University of Freiburg, Freiburg, Germany
| | - Zaid Aqrawe
- Department of Anatomy & Medical Imaging, The University of Auckland, Auckland, New Zealand
| | - Maria Asplund
- BrainLinks-BrainTools Center, University of Freiburg, Freiburg, Germany
- Department of Microsystems Engineering (IMTEK), University of Freiburg, Freiburg, Germany
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26
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Boehler C, Oberueber F, Asplund M. Tuning drug delivery from conducting polymer films for accurately controlled release of charged molecules. J Control Release 2019; 304:173-180. [PMID: 31096016 DOI: 10.1016/j.jconrel.2019.05.017] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Accepted: 05/12/2019] [Indexed: 02/01/2023]
Abstract
Spatio-temporally controlled drug release based on conducting polymer films offers a powerful technology to improve the tissue integration for implantable neuroprobes. We here explore the release efficiency of such systems in order to improve the understanding of the release mechanism and allow for optimized implementation of this technology into future drug release applications. By exposing drug loaded PEDOT coatings of different thicknesses to a multitude of release signals, along with optimizing the steps during the polymer synthesis, we could identify a highly reproducible electrostatically controlled drug release next to a slow diffusion driven release component. The release efficiency was moreover observed to be higher for a cyclic voltammetry signal in comparison to release driven by a constant potential. Biphasic current pulses, as used during neural stimulation, did not allow for long enough diffusion times to yield efficient active drug expulsion from the polymer films. A quantitative analysis could confirm an overall linear dependency between drug release and film thickness. The amount of drug released in response to the trigger signals was however not linearly correlated with the amount of charge applied. By combining these findings we could develop a model which accurately describes the drug release mechanism from a PEDOT film. The proposed model thereby points the way for how actively controlled, and diffusion related, release can be tuned for obtaining delivery dynamics tailored to specific applications.
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Affiliation(s)
- Christian Boehler
- BrainLinks-BrainTools Center, University of Freiburg, Germany; Department of Microsystems Engineering (IMTEK), University of Freiburg, Germany.
| | - Felix Oberueber
- BrainLinks-BrainTools Center, University of Freiburg, Germany; Department of Microsystems Engineering (IMTEK), University of Freiburg, Germany
| | - Maria Asplund
- BrainLinks-BrainTools Center, University of Freiburg, Germany; Department of Microsystems Engineering (IMTEK), University of Freiburg, Germany
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27
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Asplund M, Kjartansdóttir KR, Mollerup S, Vinner L, Fridholm H, Herrera JAR, Friis-Nielsen J, Hansen TA, Jensen RH, Nielsen IB, Richter SR, Rey-Iglesia A, Matey-Hernandez ML, Alquezar-Planas DE, Olsen PVS, Sicheritz-Pontén T, Willerslev E, Lund O, Brunak S, Mourier T, Nielsen LP, Izarzugaza JMG, Hansen AJ. Contaminating viral sequences in high-throughput sequencing viromics: a linkage study of 700 sequencing libraries. Clin Microbiol Infect 2019; 25:1277-1285. [PMID: 31059795 DOI: 10.1016/j.cmi.2019.04.028] [Citation(s) in RCA: 81] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Revised: 04/12/2019] [Accepted: 04/18/2019] [Indexed: 12/11/2022]
Abstract
OBJECTIVES Sample preparation for high-throughput sequencing (HTS) includes treatment with various laboratory components, potentially carrying viral nucleic acids, the extent of which has not been thoroughly investigated. Our aim was to systematically examine a diverse repertoire of laboratory components used to prepare samples for HTS in order to identify contaminating viral sequences. METHODS A total of 322 samples of mainly human origin were analysed using eight protocols, applying a wide variety of laboratory components. Several samples (60% of human specimens) were processed using different protocols. In total, 712 sequencing libraries were investigated for viral sequence contamination. RESULTS Among sequences showing similarity to viruses, 493 were significantly associated with the use of laboratory components. Each of these viral sequences had sporadic appearance, only being identified in a subset of the samples treated with the linked laboratory component, and some were not identified in the non-template control samples. Remarkably, more than 65% of all viral sequences identified were within viral clusters linked to the use of laboratory components. CONCLUSIONS We show that high prevalence of contaminating viral sequences can be expected in HTS-based virome data and provide an extensive list of novel contaminating viral sequences that can be used for evaluation of viral findings in future virome and metagenome studies. Moreover, we show that detection can be problematic due to stochastic appearance and limited non-template controls. Although the exact origin of these viral sequences requires further research, our results support laboratory-component-linked viral sequence contamination of both biological and synthetic origin.
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Affiliation(s)
- M Asplund
- Centre for GeoGenetics, Natural History Museum of Denmark, University of Copenhagen, Copenhagen, Denmark.
| | - K R Kjartansdóttir
- Centre for GeoGenetics, Natural History Museum of Denmark, University of Copenhagen, Copenhagen, Denmark
| | - S Mollerup
- Centre for GeoGenetics, Natural History Museum of Denmark, University of Copenhagen, Copenhagen, Denmark
| | - L Vinner
- Centre for GeoGenetics, Natural History Museum of Denmark, University of Copenhagen, Copenhagen, Denmark
| | - H Fridholm
- Centre for GeoGenetics, Natural History Museum of Denmark, University of Copenhagen, Copenhagen, Denmark; Department of Autoimmunology and Biomarkers, Statens Serum Institut, Copenhagen, Denmark
| | - J A R Herrera
- Disease Systems Biology Programme, Panum Instituttet, Copenhagen, Denmark; Department of Bio and Health Informatics, Technical University of Denmark, Lyngby, Denmark
| | - J Friis-Nielsen
- Department of Bio and Health Informatics, Technical University of Denmark, Lyngby, Denmark
| | - T A Hansen
- Centre for GeoGenetics, Natural History Museum of Denmark, University of Copenhagen, Copenhagen, Denmark
| | - R H Jensen
- Centre for GeoGenetics, Natural History Museum of Denmark, University of Copenhagen, Copenhagen, Denmark
| | - I B Nielsen
- Centre for GeoGenetics, Natural History Museum of Denmark, University of Copenhagen, Copenhagen, Denmark
| | - S R Richter
- Centre for GeoGenetics, Natural History Museum of Denmark, University of Copenhagen, Copenhagen, Denmark
| | - A Rey-Iglesia
- Centre for GeoGenetics, Natural History Museum of Denmark, University of Copenhagen, Copenhagen, Denmark
| | - M L Matey-Hernandez
- Department of Bio and Health Informatics, Technical University of Denmark, Lyngby, Denmark
| | - D E Alquezar-Planas
- Centre for GeoGenetics, Natural History Museum of Denmark, University of Copenhagen, Copenhagen, Denmark
| | - P V S Olsen
- Centre for GeoGenetics, Natural History Museum of Denmark, University of Copenhagen, Copenhagen, Denmark
| | - T Sicheritz-Pontén
- Centre for GeoGenetics, Natural History Museum of Denmark, University of Copenhagen, Copenhagen, Denmark; Centre of Excellence for Omics-Driven Computational Biodiscovery, AIMST University, Kedah, Malaysia
| | - E Willerslev
- Centre for GeoGenetics, Natural History Museum of Denmark, University of Copenhagen, Copenhagen, Denmark
| | - O Lund
- Department of Bio and Health Informatics, Technical University of Denmark, Lyngby, Denmark
| | - S Brunak
- Disease Systems Biology Programme, Panum Instituttet, Copenhagen, Denmark; Department of Bio and Health Informatics, Technical University of Denmark, Lyngby, Denmark
| | - T Mourier
- Centre for GeoGenetics, Natural History Museum of Denmark, University of Copenhagen, Copenhagen, Denmark
| | - L P Nielsen
- Department of Autoimmunology and Biomarkers, Statens Serum Institut, Copenhagen, Denmark
| | - J M G Izarzugaza
- Department of Bio and Health Informatics, Technical University of Denmark, Lyngby, Denmark
| | - A J Hansen
- Centre for GeoGenetics, Natural History Museum of Denmark, University of Copenhagen, Copenhagen, Denmark.
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28
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Kleber C, Lienkamp K, Rühe J, Asplund M. Electrochemically Controlled Drug Release from a Conducting Polymer Hydrogel (PDMAAp/PEDOT) for Local Therapy and Bioelectronics. Adv Healthc Mater 2019; 8:e1801488. [PMID: 30835957 DOI: 10.1002/adhm.201801488] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Revised: 02/05/2019] [Indexed: 12/27/2022]
Abstract
In this study, the release of fluorescein from a photo-crosslinked conducting polymer hydrogel made from a hydrogel precursor poly(dimethylacrylamide-co-4-methacryloyloxy benzophenone (5%)-co-4-styrenesulfonate (2.5%)) (PDMAAp) and the conducting polymer poly(3,4-ethylenedioxythiophene) (PEDOT) is investigated. Fluorescein, here used as a model for a drug, is actively released through application of an electrical trigger signal. The detected quantity is more than six times higher in comparison to that released from a conventional PEDOT/polysterene sulfonate (PSS) system. Release profiles, drug dose, and timing can be tailored by the application of different trigger signals and pretreatments. To demonstrate that the novel drug release system can be used for a drug relevant for local delivery to a neural interface, experiments are furthermore performed with the anti-inflammatory drug dexamethasone (Dex). The conducting polymer hydrogel facilitates the active release of Dex, in comparison to the previously used PEDOT/Dex. It is suggested that PEDOT/PDMAAp is an interesting alternative for conducting polymer based drug release systems, with the potential to offer more volume for storage, yet retaining the excellent electrochemical properties known for PEDOT electrodes.
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Affiliation(s)
- Carolin Kleber
- Department of Microsystems Engineering, Albert-Ludwigs University, Freiburg, Germany
- Brainlinks-Braintools, Albert-Ludwigs University, Freiburg, 79110, Germany
| | - Karen Lienkamp
- Department of Microsystems Engineering, Albert-Ludwigs University, Freiburg, Germany
- FIT Freiburg Centre for Interactive Materials and Bioinspired Technologies, Albert-Ludwigs University, Freiburg, Germany
| | - Jürgen Rühe
- Department of Microsystems Engineering, Albert-Ludwigs University, Freiburg, Germany
- Brainlinks-Braintools, Albert-Ludwigs University, Freiburg, 79110, Germany
- FIT Freiburg Centre for Interactive Materials and Bioinspired Technologies, Albert-Ludwigs University, Freiburg, Germany
| | - Maria Asplund
- Department of Microsystems Engineering, Albert-Ludwigs University, Freiburg, Germany
- Brainlinks-Braintools, Albert-Ludwigs University, Freiburg, 79110, Germany
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29
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Boehler C, Asplund M. PEDOT as a high charge injection material for low-frequency stimulation. Annu Int Conf IEEE Eng Med Biol Soc 2018; 2018:2202-2205. [PMID: 30440842 DOI: 10.1109/embc.2018.8512597] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Alternating current stimulation (ACS) provides a versatile tool for modulating brain activity and presents a promising strategy for the treatment of neurological disorders like Parkinson's disease or epilepsy. Stimulation of neural tissue at low-frequency however poses new challenges on conventional electrode materials which support limited charge transfer in the desired frequency range, from less than 0.1 Hz to several tens of Hz. In our study we address this challenge by investigating the charge transfer properties of PEDOT/PSS coatings for low-frequency applications, focusing on the impact of the polymer bulk. PEDOT films of various thicknesses were exposed to low-frequency as well as DC stimulation textbfin vitro and compared to Pt and IrOx electrodes as controls. The charge injection performance of the metallic substrates could be substantially improved already by a thin PEDOT coating. Additionally a linear dependency between charge injection and polymer thickness suggests that PEDOT coatings are promising as materials for future ACS applications.
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30
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Fiáth R, Hofer KT, Csikós V, Horváth D, Nánási T, Tóth K, Pothof F, Böhler C, Asplund M, Ruther P, Ulbert I. Long-term recording performance and biocompatibility of chronically implanted cylindrically-shaped, polymer-based neural interfaces. ACTA ACUST UNITED AC 2018; 63:301-315. [DOI: 10.1515/bmt-2017-0154] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Accepted: 11/20/2017] [Indexed: 12/12/2022]
Abstract
Abstract
Stereo-electroencephalography depth electrodes, regularly implanted into drug-resistant patients with focal epilepsy to localize the epileptic focus, have a low channel count (6–12 macro- or microelectrodes), limited spatial resolution (0.5–1 cm) and large contact area of the recording sites (~mm2). Thus, they are not suited for high-density local field potential and multiunit recordings. In this paper, we evaluated the long-term electrophysiological recording performance and histocompatibility of a neural interface consisting of 32 microelectrodes providing a physical shape similar to clinical devices. The cylindrically-shaped depth probes made of polyimide (PI) were chronically implanted for 13 weeks into the brain of rats, while cortical or thalamic activity (local field potentials, single-unit and multi-unit activity) was recorded regularly to monitor the temporal change of several features of the electrophysiological performance. To examine the tissue reaction around the probe, neuron-selective and astroglia-selective immunostaining methods were applied. Stable single-unit and multi-unit activity were recorded for several weeks with the implanted depth probes and a weak or moderate tissue reaction was found around the probe track. Our data on biocompatibility presented here and in vivo experiments in non-human primates provide a strong indication that this type of neural probe can be applied in stereo-electroencephalography recordings of up to 2 weeks in humans targeting the localization of epileptic foci providing an increased spatial resolution and the ability to monitor local field potentials and neuronal spiking activity.
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31
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Heizmann S, Kilias A, Ruther P, Egert U, Asplund M. Active Control of Dye Release for Neuronal Tracing Using PEDOT-PSS Coated Electrodes. IEEE Trans Neural Syst Rehabil Eng 2018; 26:299-306. [DOI: 10.1109/tnsre.2016.2606559] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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32
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Omland SH, Wettergren EE, Mollerup S, Asplund M, Mourier T, Hansen AJ, Gniadecki R. Correction to: Cancer associated fibroblasts (CAFs) are activated in cutaneous basal cell carcinoma and in the peritumoural skin. BMC Cancer 2018; 18:111. [PMID: 29382305 PMCID: PMC5791215 DOI: 10.1186/s12885-018-3987-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Accepted: 01/03/2018] [Indexed: 11/10/2022] Open
Affiliation(s)
- Silje Haukali Omland
- Department of Dermato-Venerology, Bispebjerg University Hospital, Bispebjerg Bakke 23, 2400, Copenhagen, Nordvest, Denmark.
| | - Erika Elgstrand Wettergren
- Department of Dermato-Venerology, Bispebjerg University Hospital, Bispebjerg Bakke 23, 2400, Copenhagen, Nordvest, Denmark
| | - Sarah Mollerup
- Centre for GeoGenetics, Natural History Museum, University of Copenhagen, Copenhagen, Denmark
| | - Maria Asplund
- Centre for GeoGenetics, Natural History Museum, University of Copenhagen, Copenhagen, Denmark
| | - Tobias Mourier
- Centre for GeoGenetics, Natural History Museum, University of Copenhagen, Copenhagen, Denmark
| | - Anders Johannes Hansen
- Centre for GeoGenetics, Natural History Museum, University of Copenhagen, Copenhagen, Denmark
| | - Robert Gniadecki
- Division of Dermatology, Faculty of Medicine, University of Alberta, Edmonton, Canada
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33
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Omland SH, Wettergren EE, Mollerup S, Asplund M, Mourier T, Hansen AJ, Gniadecki R. Cancer associated fibroblasts (CAFs) are activated in cutaneous basal cell carcinoma and in the peritumoural skin. BMC Cancer 2017; 17:675. [PMID: 28987144 PMCID: PMC5806272 DOI: 10.1186/s12885-017-3663-0] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Accepted: 09/29/2017] [Indexed: 12/21/2022] Open
Abstract
Background Cutaneous basal cell carcinoma (BCC) is the commonest cancer worldwide. BCC is locally invasive and the surrounding stromal microenvironment is pivotal for tumourigenesis. Cancer associated fibroblasts (CAFs) in the microenvironment are essential for tumour growth in a variety of neoplasms but their role in BCC is poorly understood. Methods Material included facial BCC and control skin from the peritumoural area and from the buttocks. With next-generation sequencing (NGS) we compared mRNA expression between BCC and peritumoural skin. qRT-PCR, immunohistochemical and immunofluorescent staining were performed to validate the NGS results and to investigate CAF-related cyto-and chemokines. Results NGS revealed upregulation of 65 genes in BCC coding for extracellular matrix components pointing at CAF-related matrix remodeling. qRT-PCR showed increased mRNA expression of CAF markers FAP-α, PDGFR-β and prolyl-4-hydroxylase in BCC. Peritumoural skin (but not buttock skin) also exhibited high expression of PDGFR-β and prolyl-4-hydroxylase but not FAP-α. We found a similar pattern for the CAF-associated chemokines CCL17, CCL18, CCL22, CCL25, CXCL12 and IL6 with high expression in BCC and peritumoural skin but absence in buttock skin. Immunofluorescence revealed correlation between FAP-α and PDGFR-β and CXCL12 and CCL17. Conclusion Matrix remodeling is the most prominent molecular feature of BCC. CAFs are present within BCC stroma and associated with increased expression of chemokines involved in tumour progression and immunosuppression (CXCL12, CCL17). Fibroblasts from chronically sun-exposed skin near tumours show gene expression patterns resembling that of CAFs, indicating that stromal fibroblasts in cancer-free surgical BCC margins exhibit a tumour promoting phenotype. Electronic supplementary material The online version of this article (doi: 10.1186/s12885-017-3663-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Silje Haukali Omland
- Department of Dermato-Venerology, Bispebjerg University Hospital, Bispebjerg Bakke 23, 2400, Copenhagen, Nordvest, Denmark.
| | - Erika Elgstrand Wettergren
- Department of Dermato-Venerology, Bispebjerg University Hospital, Bispebjerg Bakke 23, 2400, Copenhagen, Nordvest, Denmark
| | - Sarah Mollerup
- Centre for GeoGenetics, Natural History Museum, University of Copenhagen, Copenhagen, Denmark
| | - Maria Asplund
- Centre for GeoGenetics, Natural History Museum, University of Copenhagen, Copenhagen, Denmark
| | - Tobias Mourier
- Centre for GeoGenetics, Natural History Museum, University of Copenhagen, Copenhagen, Denmark
| | - Anders Johannes Hansen
- Centre for GeoGenetics, Natural History Museum, University of Copenhagen, Copenhagen, Denmark
| | - Robert Gniadecki
- Department of Dermato-Venerology, Bispebjerg University Hospital, Bispebjerg Bakke 23, 2400, Copenhagen, Nordvest, Denmark.,Division of Dermatology, Faculty of Medicine, University of Alberta, Edmonton, Canada
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Kleber C, Bruns M, Lienkamp K, Rühe J, Asplund M. An interpenetrating, microstructurable and covalently attached conducting polymer hydrogel for neural interfaces. Acta Biomater 2017; 58:365-375. [PMID: 28578108 DOI: 10.1016/j.actbio.2017.05.056] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Revised: 05/19/2017] [Accepted: 05/30/2017] [Indexed: 01/25/2023]
Abstract
This study presents a new conducting polymer hydrogel (CPH) system, consisting of the synthetic hydrogel P(DMAA-co-5%MABP-co-2,5%SSNa) and the conducting polymer (CP) poly(3,4-ethylenedioxythiophene) (PEDOT), intended as coating material for neural interfaces. The composite material can be covalently attached to the surface electrode, can be patterned by a photolithographic process to influence selected electrode sites only and forms an interpenetrating network. The hybrid material was characterized using cyclic voltammetry (CV), impedance spectroscopy (EIS) and X-ray photoelectron spectroscopy (XPS), which confirmed a homogeneous distribution of PEDOT throughout all CPH layers. The CPH exhibited a 2,5 times higher charge storage capacity (CSC) and a reduced impedance when compared to the bare hydrogel. Electrochemical stability was proven over at least 1000 redox cycles. Non-toxicity was confirmed using an elution toxicity test together with a neuroblastoma cell-line. The described material shows great promise for surface modification of neural probes making it possible to combine the beneficial properties of the hydrogel with the excellent electronic properties necessary for high quality neural microelectrodes. STATEMENT OF SIGNIFICANCE Conductive polymer hydrogels have emerged as a promising new class of materials to functionalize electrode surfaces for enhanced neural interfaces and drug delivery. Common weaknesses of such systems are delamination from the connection surface, and the lack of suitable patterning methods for confining the gel to the selected electrode site. Various studies have reported on conductive polymer hydrogels addressing one of these challenges. In this study we present a new composite material which offers, for the first time, the unique combination of properties: it can be covalently attached to the substrate, forms an interpenetrating network, shows excellent electrical properties and can be patterned via UV-irradiation through a structured mask.
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Affiliation(s)
- Carolin Kleber
- BrainLinks-BrainTools Center, University of Freiburg, Germany; Department of Microsystems Engineering (IMTEK), University of Freiburg, Germany.
| | - Michael Bruns
- Institute for Applied Materials (IAM) and Karlsruhe Nano Micro Facility (KNMF), Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Karen Lienkamp
- Department of Microsystems Engineering (IMTEK), University of Freiburg, Germany
| | - Jürgen Rühe
- BrainLinks-BrainTools Center, University of Freiburg, Germany; Department of Microsystems Engineering (IMTEK), University of Freiburg, Germany
| | - Maria Asplund
- BrainLinks-BrainTools Center, University of Freiburg, Germany; Department of Microsystems Engineering (IMTEK), University of Freiburg, Germany
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Boehler C, Oberueber F, Stieglitz T, Asplund M. Nanostructured platinum as an electrochemically and mechanically stable electrode coating. Annu Int Conf IEEE Eng Med Biol Soc 2017; 2017:1058-1061. [PMID: 29060056 DOI: 10.1109/embc.2017.8037009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Nanostructured materials exhibit large electrochemical surface areas and are thus of high interest for neural interfaces where low impedance and high charge transfer characteristics are desired. While progress in nanotechnology successively enabled smaller feature sizes and thus improved electrochemical properties, concerns were raised with respect to the mechanical stability of such nano structures for use in neural applications. In our study we address these concerns by investigating the mechanical and electrochemical stability of nanostructured platinum. Neural probes with nano-Pt were exposed to exaggerated stress tests resembling insertion into neural tissue over 60 mm distance or long-term stimulation over 240 M biphasic current pulses. Thereby only insignificant changes in electrochemical properties and morphological appearance could be observed in response to the test, proving that nanostructured platinum exhibits outstanding stability. With this finding, a major concern in using nanostructured materials for interfacing neural tissue could be eliminated, demonstrating the high potential of nanostructured platinum for neuroprosthetic devices.
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Boehler C, Kleber C, Martini N, Xie Y, Dryg I, Stieglitz T, Hofmann U, Asplund M. Actively controlled release of Dexamethasone from neural microelectrodes in a chronic in vivo study. Biomaterials 2017; 129:176-187. [DOI: 10.1016/j.biomaterials.2017.03.019] [Citation(s) in RCA: 86] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2016] [Revised: 03/08/2017] [Accepted: 03/12/2017] [Indexed: 10/20/2022]
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Mollerup S, Fridholm H, Vinner L, Kjartansdóttir KR, Friis-Nielsen J, Asplund M, Herrera JAR, Steiniche T, Mourier T, Brunak S, Willerslev E, Izarzugaza JMG, Hansen AJ, Nielsen LP. Cutavirus in Cutaneous Malignant Melanoma. Emerg Infect Dis 2017; 23:363-365. [PMID: 28098541 PMCID: PMC5324802 DOI: 10.3201/eid2302.161564] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
A novel human protoparvovirus related to human bufavirus and preliminarily named cutavirus has been discovered. We detected cutavirus in a sample of cutaneous malignant melanoma by using viral enrichment and high-throughput sequencing. The role of cutaviruses in cutaneous cancers remains to be investigated.
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Boehler C, Oberueber F, Schlabach S, Stieglitz T, Asplund M. Long-Term Stable Adhesion for Conducting Polymers in Biomedical Applications: IrOx and Nanostructured Platinum Solve the Chronic Challenge. ACS Appl Mater Interfaces 2017; 9:189-197. [PMID: 27936546 DOI: 10.1021/acsami.6b13468] [Citation(s) in RCA: 85] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Conducting polymers (CPs) have frequently been described as outstanding coating materials for neural microelectrodes, providing significantly reduced impedance or higher charge injection compared to pure metals. Usability has until now, however, been limited by poor adhesion of polymers like poly(3,4-ethylenedioxythiophene) (PEDOT) to metallic substrates, ultimately precluding long-term applications. The aim of this study was to overcome this weakness of CPs by introducing two novel adhesion improvement strategies that can easily be integrated with standard microelectrode fabrication processes. Iridium Oxide (IrOx) demonstrated exceptional stability for PEDOT coatings, resulting in polymer survival over 10 000 redox cycles and 110 days under accelerated aging conditions at 60 °C. Nanostructured Pt was furthermore introduced as a purely mechanical adhesion promoter providing 10-fold adhesion improvement compared to smooth Pt substrates by simply altering the morphology of Pt. This layer can be realized in a very simple process that is compatible with any electrode design, turning nanostructured Pt into a universal adhesion layer for CP coatings. By the introduction of these adhesion-promoting strategies, the weakness of CP-based neural probes can ultimately be eliminated and true long-term stable use of PEDOT on neural probes will be possible in future electrode generations.
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Affiliation(s)
- Christian Boehler
- BrainLinks-BrainTools Center & Department of Microsystems Engineering (IMTEK), University of Freiburg , Georges-Koehler-Allee 102, 79110 Freiburg, Germany
| | - Felix Oberueber
- BrainLinks-BrainTools Center & Department of Microsystems Engineering (IMTEK), University of Freiburg , Georges-Koehler-Allee 102, 79110 Freiburg, Germany
| | - Sabine Schlabach
- Institute for Applied Materials (IAM) and Karlsruhe Nano Micro Facility (KNMF), Karlsruhe Institute of Technology (KIT) , Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
| | - Thomas Stieglitz
- BrainLinks-BrainTools Center & Department of Microsystems Engineering (IMTEK), University of Freiburg , Georges-Koehler-Allee 102, 79110 Freiburg, Germany
| | - Maria Asplund
- BrainLinks-BrainTools Center & Department of Microsystems Engineering (IMTEK), University of Freiburg , Georges-Koehler-Allee 102, 79110 Freiburg, Germany
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Mueller M, Boehler C, Jaeger J, Asplund M, Stieglitz T. A double-sided fabrication process for intrafascicular parylene C based electrode arrays. Annu Int Conf IEEE Eng Med Biol Soc 2016; 2016:2798-2801. [PMID: 28268899 DOI: 10.1109/embc.2016.7591311] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
After the development of a single-sided fabrication process for intrafascicular parylene C based electrode arrays tests showed that an increase in integration density can only be achieved by a double-side process. The process uses 25 μm thick platinum iridium foil, which is thinned down with the laser and sandwiched between two 10 μm thick parylene C layers. Utilizing a picosecond laser (355 nm Nd:YVO4) it was possible to fabricate 40 μm thick electrodes that can be implanted directly in the nerve without relying on additional support layers like chitosan or silk. The fabricated samples feature three 80 μm diameter electrodes on each side and a large ground electrode that is opened to both sides. Impedance mismatches from front to back side as a result of the fabrication process are compensated by electrochemical deposition of nanostructured platinum. This step makes it possible to bring the impedances of the small electrodes down to the range of just a few kΩ at 1 kHz and illustrate the additionally gained surface due to the picosecond laser ablation on the front side electrodes. The safely injectable charge per pulse was found to be 635.75 μC/cm2 for such coated electrodes. Optical investigations show that this fabrication process offers an alternative to established lithographic processes for thin and flexible electrode arrays in neural implants.
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Schopf A, Boehler C, Asplund M. Analytical methods to determine electrochemical factors in electrotaxis setups and their implications for experimental design. Bioelectrochemistry 2016; 109:41-8. [DOI: 10.1016/j.bioelechem.2015.12.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Revised: 12/18/2015] [Accepted: 12/29/2015] [Indexed: 10/22/2022]
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Friis-Nielsen J, Kjartansdóttir KR, Mollerup S, Asplund M, Mourier T, Jensen RH, Hansen TA, Rey-Iglesia A, Richter SR, Nielsen IB, Alquezar-Planas DE, Olsen PVS, Vinner L, Fridholm H, Nielsen LP, Willerslev E, Sicheritz-Pontén T, Lund O, Hansen AJ, Izarzugaza JMG, Brunak S. Identification of Known and Novel Recurrent Viral Sequences in Data from Multiple Patients and Multiple Cancers. Viruses 2016; 8:E53. [PMID: 26907326 PMCID: PMC4776208 DOI: 10.3390/v8020053] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Revised: 01/29/2016] [Accepted: 02/05/2016] [Indexed: 12/17/2022] Open
Abstract
Virus discovery from high throughput sequencing data often follows a bottom-up approach where taxonomic annotation takes place prior to association to disease. Albeit effective in some cases, the approach fails to detect novel pathogens and remote variants not present in reference databases. We have developed a species independent pipeline that utilises sequence clustering for the identification of nucleotide sequences that co-occur across multiple sequencing data instances. We applied the workflow to 686 sequencing libraries from 252 cancer samples of different cancer and tissue types, 32 non-template controls, and 24 test samples. Recurrent sequences were statistically associated to biological, methodological or technical features with the aim to identify novel pathogens or plausible contaminants that may associate to a particular kit or method. We provide examples of identified inhabitants of the healthy tissue flora as well as experimental contaminants. Unmapped sequences that co-occur with high statistical significance potentially represent the unknown sequence space where novel pathogens can be identified.
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Affiliation(s)
- Jens Friis-Nielsen
- Center for Biological Sequence Analysis, Department of Systems Biology, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark.
| | - Kristín Rós Kjartansdóttir
- Centre for GeoGenetics, Natural History Museum of Denmark, University of Copenhagen, DK-1350 Copenhagen, Denmark.
| | - Sarah Mollerup
- Centre for GeoGenetics, Natural History Museum of Denmark, University of Copenhagen, DK-1350 Copenhagen, Denmark.
| | - Maria Asplund
- Centre for GeoGenetics, Natural History Museum of Denmark, University of Copenhagen, DK-1350 Copenhagen, Denmark.
| | - Tobias Mourier
- Centre for GeoGenetics, Natural History Museum of Denmark, University of Copenhagen, DK-1350 Copenhagen, Denmark.
| | - Randi Holm Jensen
- Centre for GeoGenetics, Natural History Museum of Denmark, University of Copenhagen, DK-1350 Copenhagen, Denmark.
| | - Thomas Arn Hansen
- Centre for GeoGenetics, Natural History Museum of Denmark, University of Copenhagen, DK-1350 Copenhagen, Denmark.
| | - Alba Rey-Iglesia
- Centre for GeoGenetics, Natural History Museum of Denmark, University of Copenhagen, DK-1350 Copenhagen, Denmark.
| | - Stine Raith Richter
- Centre for GeoGenetics, Natural History Museum of Denmark, University of Copenhagen, DK-1350 Copenhagen, Denmark.
| | - Ida Broman Nielsen
- Centre for GeoGenetics, Natural History Museum of Denmark, University of Copenhagen, DK-1350 Copenhagen, Denmark.
| | - David E Alquezar-Planas
- Centre for GeoGenetics, Natural History Museum of Denmark, University of Copenhagen, DK-1350 Copenhagen, Denmark.
| | - Pernille V S Olsen
- Centre for GeoGenetics, Natural History Museum of Denmark, University of Copenhagen, DK-1350 Copenhagen, Denmark.
| | - Lasse Vinner
- Centre for GeoGenetics, Natural History Museum of Denmark, University of Copenhagen, DK-1350 Copenhagen, Denmark.
| | - Helena Fridholm
- Centre for GeoGenetics, Natural History Museum of Denmark, University of Copenhagen, DK-1350 Copenhagen, Denmark.
| | - Lars Peter Nielsen
- Department of Autoimmunology and Biomarkers, Statens Serum Institut, DK-2300 Copenhagen S, Denmark.
| | - Eske Willerslev
- Centre for GeoGenetics, Natural History Museum of Denmark, University of Copenhagen, DK-1350 Copenhagen, Denmark.
| | - Thomas Sicheritz-Pontén
- Center for Biological Sequence Analysis, Department of Systems Biology, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark.
| | - Ole Lund
- Center for Biological Sequence Analysis, Department of Systems Biology, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark.
| | - Anders Johannes Hansen
- Centre for GeoGenetics, Natural History Museum of Denmark, University of Copenhagen, DK-1350 Copenhagen, Denmark.
| | - Jose M G Izarzugaza
- Center for Biological Sequence Analysis, Department of Systems Biology, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark.
| | - Søren Brunak
- Center for Biological Sequence Analysis, Department of Systems Biology, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark.
- NNF Center for Protein Research, University of Copenhagen, Blegdamsvej 3B, DK-2200 Copenhagen, Denmark.
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Howes LM, Casey AR, Asplund M, Keller SC, Yong D, Nataf DM, Poleski R, Lind K, Kobayashi C, Owen CI, Ness M, Bessell MS, Da Costa GS, Schmidt BP, Tisserand P, Udalski A, Szymański MK, Soszyński I, Pietrzyński G, Ulaczyk K, Wyrzykowski Ł, Pietrukowicz P, Skowron J, Kozłowski S, Mróz P. Extremely metal-poor stars from the cosmic dawn in the bulge of the Milky Way. Nature 2015; 527:484-7. [PMID: 26560034 DOI: 10.1038/nature15747] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2015] [Accepted: 08/24/2015] [Indexed: 11/09/2022]
Abstract
The first stars are predicted to have formed within 200 million years after the Big Bang, initiating the cosmic dawn. A true first star has not yet been discovered, although stars with tiny amounts of elements heavier than helium ('metals') have been found in the outer regions ('halo') of the Milky Way. The first stars and their immediate successors should, however, preferentially be found today in the central regions ('bulges') of galaxies, because they formed in the largest over-densities that grew gravitationally with time. The Milky Way bulge underwent a rapid chemical enrichment during the first 1-2 billion years, leading to a dearth of early, metal-poor stars. Here we report observations of extremely metal-poor stars in the Milky Way bulge, including one star with an iron abundance about 10,000 times lower than the solar value without noticeable carbon enhancement. We confirm that most of the metal-poor bulge stars are on tight orbits around the Galactic Centre, rather than being halo stars passing through the bulge, as expected for stars formed at redshifts greater than 15. Their chemical compositions are in general similar to typical halo stars of the same metallicity although intriguing differences exist, including lower abundances of carbon.
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Affiliation(s)
- L M Howes
- Research School of Astronomy and Astrophysics, Australian National University, Australian Capital Territory 2601, Australia
| | - A R Casey
- Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA, UK
| | - M Asplund
- Research School of Astronomy and Astrophysics, Australian National University, Australian Capital Territory 2601, Australia
| | - S C Keller
- Research School of Astronomy and Astrophysics, Australian National University, Australian Capital Territory 2601, Australia
| | - D Yong
- Research School of Astronomy and Astrophysics, Australian National University, Australian Capital Territory 2601, Australia
| | - D M Nataf
- Research School of Astronomy and Astrophysics, Australian National University, Australian Capital Territory 2601, Australia
| | - R Poleski
- Warsaw University Observatory, Aleje Ujazdowskie 4, 00-478 Warszawa, Poland.,Department of Astronomy, Ohio State University, 140 West 18th Avenue, Columbus, Ohio 43210, USA
| | - K Lind
- Department of Physics and Astronomy, Division of Astronomy and Space Physics, Uppsala University, Box 516, SE-751 20 Uppsala, Sweden
| | - C Kobayashi
- Research School of Astronomy and Astrophysics, Australian National University, Australian Capital Territory 2601, Australia.,School of Physics, Astronomy and Mathematics, Centre for Astrophysics Research, University of Hertfordshire, College Lane, Hatfield AL10 9AB, UK
| | - C I Owen
- Research School of Astronomy and Astrophysics, Australian National University, Australian Capital Territory 2601, Australia
| | - M Ness
- Max-Planck-Institut für Astronomie, Königstuhl 17, D-69117 Heidelberg, Germany
| | - M S Bessell
- Research School of Astronomy and Astrophysics, Australian National University, Australian Capital Territory 2601, Australia
| | - G S Da Costa
- Research School of Astronomy and Astrophysics, Australian National University, Australian Capital Territory 2601, Australia
| | - B P Schmidt
- Research School of Astronomy and Astrophysics, Australian National University, Australian Capital Territory 2601, Australia
| | - P Tisserand
- Research School of Astronomy and Astrophysics, Australian National University, Australian Capital Territory 2601, Australia.,Sorbonne Universités, UPMC Université Paris 6 et CNRS, UMR 7095, Institut d'Astrophysique de Paris, 98 bis Boulevard Arago, 75014 Paris, France
| | - A Udalski
- Warsaw University Observatory, Aleje Ujazdowskie 4, 00-478 Warszawa, Poland
| | - M K Szymański
- Warsaw University Observatory, Aleje Ujazdowskie 4, 00-478 Warszawa, Poland
| | - I Soszyński
- Warsaw University Observatory, Aleje Ujazdowskie 4, 00-478 Warszawa, Poland
| | - G Pietrzyński
- Warsaw University Observatory, Aleje Ujazdowskie 4, 00-478 Warszawa, Poland.,Universidad de Concepción, Departamento de Astronomia, Casilla 160-C, Concepción, Chile
| | - K Ulaczyk
- Warsaw University Observatory, Aleje Ujazdowskie 4, 00-478 Warszawa, Poland.,Department of Physics, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, UK
| | - Ł Wyrzykowski
- Warsaw University Observatory, Aleje Ujazdowskie 4, 00-478 Warszawa, Poland
| | - P Pietrukowicz
- Warsaw University Observatory, Aleje Ujazdowskie 4, 00-478 Warszawa, Poland
| | - J Skowron
- Warsaw University Observatory, Aleje Ujazdowskie 4, 00-478 Warszawa, Poland
| | - S Kozłowski
- Warsaw University Observatory, Aleje Ujazdowskie 4, 00-478 Warszawa, Poland
| | - P Mróz
- Warsaw University Observatory, Aleje Ujazdowskie 4, 00-478 Warszawa, Poland
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Boehler C, Stieglitz T, Asplund M. Nanostructured platinum grass enables superior impedance reduction for neural microelectrodes. Biomaterials 2015; 67:346-53. [PMID: 26232883 DOI: 10.1016/j.biomaterials.2015.07.036] [Citation(s) in RCA: 84] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Revised: 07/17/2015] [Accepted: 07/20/2015] [Indexed: 11/27/2022]
Abstract
Micro-sized electrodes are essential for highly sensitive communication at the neural interface with superior spatial resolution. However, such small electrodes inevitably suffer from high electrical impedance and thus high levels of thermal noise deteriorating the signal to noise ratio. In order to overcome this problem, a nanostructured Pt-coating was introduced as add-on functionalization for impedance reduction of small electrodes. In comparison to platinum black deposition, all used chemicals in the deposition process are free from cytotoxic components. The grass-like nanostructure was found to reduce the impedance by almost two orders of magnitude compared to untreated samples which was lower than what could be achieved with conventional electrode coatings like IrOx or PEDOT. The realization of the Pt-grass coating is performed via a simple electrochemical process which can be applied to virtually any possible electrode type and accordingly shows potential as a universal impedance reduction strategy. Elution tests revealed non-toxicity of the Pt-grass and the coating was found to exhibit strong adhesion to the metallized substrate.
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Affiliation(s)
- C Boehler
- Department of Microsystems Engineering (IMTEK), University of Freiburg, Georges-Koehler-Allee 102, 79110 Freiburg, Germany.
| | - T Stieglitz
- Department of Microsystems Engineering (IMTEK), University of Freiburg, Georges-Koehler-Allee 102, 79110 Freiburg, Germany.
| | - M Asplund
- Department of Microsystems Engineering (IMTEK), University of Freiburg, Georges-Koehler-Allee 102, 79110 Freiburg, Germany.
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Boehler C, Asplund M. A detailed insight into drug delivery from PEDOT based on analytical methods: effects and side effects. J Biomed Mater Res A 2014; 103:1200-7. [PMID: 24912825 PMCID: PMC4342763 DOI: 10.1002/jbm.a.35252] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2014] [Revised: 05/28/2014] [Accepted: 06/04/2014] [Indexed: 12/24/2022]
Abstract
The possibility to release drugs from conducting polymers, like polypyrrole or poly(3,4-ethylenedioxythiophene) (PEDOT), has been described and investigated for a variety of different substances during the last years, showing a wide interest in these release systems. A point that has not been looked at so far however is the possibility of other substances, next to the intended ones, leaving the polymer film under the high voltage excursions during redox sweeping. In this study we target this weakness of commonly used detection methods by implementing a high precision analytical method (high-performance liquid chromatography) that allows a separation and subsequently a detailed quantification of all possible release products. We could identify a significantly more complex release behavior for a PEDOT:Dex system than has been assumed so far, revealing the active release of the monomer upon redox activation. The released EDOT could thereby be shown to result from the bulk material, causing a considerable loss of polymer (>10% during six release events) that could partly account for the observed degradation or delamination effects of drug-eluting coatings. The monomer leakage was found to be substantially higher for a PEDOT:Dex film compared to a PEDOT:PSS sample. This finding indicates an overestimation of drug release if side products are mistaken for the actual drug mass. Moreover the full picture of released substances implements the need for further studies to reduce the monomer leakage and identify possible adverse effects, especially in the perspective of releasing an anti-inflammatory substance for attenuation of the foreign body reaction toward implanted electrodes.
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Affiliation(s)
- Christian Boehler
- Freiburg Institute for Advanced Studies (FRIAS), Albert-Ludwigs-Universität, Freiburg, Germany; Department of Microsystems Engineering (IMTEK), Albert-Ludwigs-Universität Freiburg, Georges-Koehler-Allee 102, 79110, Freiburg, Germany
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Asplund M, Boehler C, Stieglitz T. Anti-inflammatory polymer electrodes for glial scar treatment: bringing the conceptual idea to future results. Front Neuroeng 2014; 7:9. [PMID: 24860493 PMCID: PMC4026681 DOI: 10.3389/fneng.2014.00009] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/30/2014] [Accepted: 04/02/2014] [Indexed: 01/03/2023]
Abstract
Conducting polymer films offer a convenient route for the functionalization of implantable microelectrodes without compromising their performance as excellent recording units. A micron thick coating, deposited on the surface of a regular metallic electrode, can elute anti-inflammatory drugs for the treatment of glial scarring as well as growth factors for the support of surrounding neurons. Electro-activation of the polymer drives the release of the substance and should ideally provide a reliable method for controlling quantity and timing of release. Driving signals in the form of a constant potential (CP), a slow redox sweep or a fast pulse are all represented in literature. Few studies present such release in vivo from actual recording and stimulating microelectronic devices. It is essential to bridge the gap between studies based on release in vitro, and the intended application, which would mean release into living and highly delicate tissue. In the biological setting, signals are limited both by available electronics and by the biological safety. Driving signals must not be harmful to tissue and also not activate the tissue in an uncontrolled manner. This review aims at shedding more light on how to select appropriate driving parameters for the polymer electrodes for the in vivo setting. It brings together information regarding activation thresholds for neurons, as well as injury thresholds, and puts this into context with what is known about efficient driving of release from conducting polymer films.
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Affiliation(s)
- Maria Asplund
- Biomedical Microtechnology, IMTEK, Albert-Ludwigs Universität Freiburg, Germany ; Freiburg Institute for Advanced Studies FRIAS, Albert-Ludwigs Universität Freiburg, Germany ; BrainLinks-BrainTools Cluster of Excellence, Albert-Ludwigs Universität Freiburg, Germany
| | - Christian Boehler
- Biomedical Microtechnology, IMTEK, Albert-Ludwigs Universität Freiburg, Germany ; Freiburg Institute for Advanced Studies FRIAS, Albert-Ludwigs Universität Freiburg, Germany ; BrainLinks-BrainTools Cluster of Excellence, Albert-Ludwigs Universität Freiburg, Germany
| | - Thomas Stieglitz
- Biomedical Microtechnology, IMTEK, Albert-Ludwigs Universität Freiburg, Germany ; BrainLinks-BrainTools Cluster of Excellence, Albert-Ludwigs Universität Freiburg, Germany
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Keller SC, Bessell MS, Frebel A, Casey AR, Asplund M, Jacobson HR, Lind K, Norris JE, Yong D, Heger A, Magic Z, Da Costa GS, Schmidt BP, Tisserand P. A single low-energy, iron-poor supernova as the source of metals in the star SMSS J031300.36−670839.3. Nature 2014; 506:463-6. [DOI: 10.1038/nature12990] [Citation(s) in RCA: 247] [Impact Index Per Article: 24.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2013] [Accepted: 12/05/2013] [Indexed: 11/09/2022]
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47
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Tvedebrink T, Asplund M, Eriksen PS, Mogensen HS, Morling N. Estimating drop-out probabilities of STR alleles accounting for stutters, detection threshold truncation and degradation. Forensic Science International: Genetics Supplement Series 2013. [DOI: 10.1016/j.fsigss.2013.10.026] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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49
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Lindgren J, Ekblad S, Asplund M, Irestig R, Burström B. Mental ill health among asylum seekers and other immigrants in Sweden. Intl J of Migration, H and SC 2012. [DOI: 10.1108/17479891211287067] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Ekblad S, Linander A, Asplund M. An exploration of the connection between two meaning perspectives: an evidence-based approach to health information delivery to vulnerable groups of Arabic- and Somali-speaking asylum seekers in a Swedish context. Glob Health Promot 2012; 19:21-31. [DOI: 10.1177/1757975912453182] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The right to health care is significant for asylum seekers, particularly as many of them have experienced traumatic life events in their home country, during flight or in their host country. Post-migration living conditions have more impact than pre-migration conditions on ill health among asylum seekers, which underscores the importance of health care-related refugee reception policies. The purpose of this article is to explore the perceived meaning of comprehensive health information provided by a nurse to Arabic- and Somali-speaking adult asylum seekers, in a Swedish context, during its introduction at the Migration Board. In our study, the endpoint was whether asylum seekers found such health information relevant, understandable and respectful. Following an oral presentation, participants filled in a questionnaire consisting of three close-ended questions. A total of 39 groups of presentation attendees included 626 asylum seekers (415 Arabic- and 211 Somali-speaking). Data were analysed with descriptive statistics. Comments underwent content analysis. We also present some socio-demographic data on these asylum seekers. Independently of gender and language, the participants expressed their gratitude for and the meaningfulness of receiving professional, fact-based information, as well as being treated with concern and respect. They indicated a great need for this and felt relieved by being listened to. They liked the pedagogic group method, the opportunity for dialogue and to practice exercising their rights. These promising results indicate that exercising the asylum-seekers’ right to receive such health information would improve future reception policies not only in Sweden, but throughout the EU. A renewed focus on communication and pedagogic skills, instead of just cultural training, should be considered for health care professionals assisting asylum seekers.
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Affiliation(s)
- Solvig Ekblad
- Department LIME (learning, informatics, management and ethics), Karolinska Institutet, Stockholm, Sweden
| | - Andrea Linander
- Department LIME (learning, informatics, management and ethics), Karolinska Institutet, Stockholm, Sweden
- Umea University, Umea, Sweden
| | - Maria Asplund
- Department LIME (learning, informatics, management and ethics), Karolinska Institutet, Stockholm, Sweden
- Primary Health Care Wasa-Carema Health Centre, Södertälje, Sweden
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