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Abrantes M, Pereira T, Silva P, Falcão M, Borme J, Alpuim P, Jacinto L. Small form factor implantable neural probe with efficient flip chip µLED for in vivo optogenetics. Biomed Microdevices 2025; 27:24. [PMID: 40439894 PMCID: PMC12122578 DOI: 10.1007/s10544-025-00754-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/14/2025] [Indexed: 06/02/2025]
Abstract
Optogenetics is a widely used tool to dissect neural circuits with optical stimulation, but it requires that light is delivered to photosensitive neurons inside the brain. Implantable neural probes with microscale LEDs (µLEDs) are an emerging approach to delivering light to the brain with superior light output control. However, approaches to integrate µLEDs in neural probes depend on complex fabrication processes. Here, we developed an implantable small form factor neural probe that integrates highly efficient commercial flip chip µLEDs using only standard lithography processes in silicon and a custom automated LED mounting approach with custom 3D-printed tools on a pick-and-place machine. The probe has a cross-sectional area under 0.013 mm2 but can output up to 2.5 mW of optical power with an irradiance of 175 mW/mm2. Due to the high plug efficiency of the LED, the neural probe can perform stimulation protocols up to 20 Hz and 80% duty cycles without surpassing estimated hotspot temperature elevations above 1 ºC. The neural probes were validated in vivo, with brain activity in the motor cortex of transgenic mice being reliably modulated by pulsed light emitted from the probe.
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Affiliation(s)
- Mafalda Abrantes
- Department of Biomedicine - Experimental Biology Unit, Faculty of Medicine, University of Porto (FMUP), Porto, 4200-319, Portugal
- International Iberian Nanotechnology Laboratory, Braga, 4715-330, Portugal
- Centro de Física das Universidades do Minho e Porto, University of Minho, Braga, 4710-057, Portugal
| | - Tiago Pereira
- Department of Biomedicine - Experimental Biology Unit, Faculty of Medicine, University of Porto (FMUP), Porto, 4200-319, Portugal
- International Iberian Nanotechnology Laboratory, Braga, 4715-330, Portugal
| | - Patrícia Silva
- Department of Biomedicine - Experimental Biology Unit, Faculty of Medicine, University of Porto (FMUP), Porto, 4200-319, Portugal
- Rise-Health - Department of Biomedicine, Faculty of Medicine, University of Porto (FMUP), Porto, 4200-319, Portugal
| | - Margarida Falcão
- Department of Biomedicine - Experimental Biology Unit, Faculty of Medicine, University of Porto (FMUP), Porto, 4200-319, Portugal
- Rise-Health - Department of Biomedicine, Faculty of Medicine, University of Porto (FMUP), Porto, 4200-319, Portugal
| | - Jérôme Borme
- International Iberian Nanotechnology Laboratory, Braga, 4715-330, Portugal
| | - Pedro Alpuim
- International Iberian Nanotechnology Laboratory, Braga, 4715-330, Portugal
- Centro de Física das Universidades do Minho e Porto, University of Minho, Braga, 4710-057, Portugal
| | - Luis Jacinto
- Department of Biomedicine - Experimental Biology Unit, Faculty of Medicine, University of Porto (FMUP), Porto, 4200-319, Portugal.
- Rise-Health - Department of Biomedicine, Faculty of Medicine, University of Porto (FMUP), Porto, 4200-319, Portugal.
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2
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Lee H, Lee S, Lee S, Lee J, Chou N, Shin H. A Highly Efficient Low-Cost Flexible Neural Probe for Scalable Mass Fabrication. ACS OMEGA 2025; 10:10733-10740. [PMID: 40124055 PMCID: PMC11923641 DOI: 10.1021/acsomega.5c01419] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/18/2025] [Revised: 02/22/2025] [Accepted: 02/26/2025] [Indexed: 03/25/2025]
Abstract
Neural probes capable of the precise recording and control of brain signals are essential tools for brain-computer interfaces and neuroscience research. However, conventional neural probes have not been widely adopted due to the high costs associated with semiconductor fabrication and complex packaging procedures. Herein, we present a breakthrough in this area in the form of a highly efficient flexible neural probe with a production cost of only 1.5 dollars per unit that can be mass-produced (1000 units within 3 days). The probe design is based on a standardized flexible printed circuit board (PCB) process that ensures large-scale producibility and minimizes device performance variation. The device features four independent neural probes that enable flexible targeting of multiple brain regions and a reusable interface PCB that minimizes packaging complexity. The neural signal recording performance of the fabricated probe is comparable to that of traditional silicon-based probes and is scalable with eight electrodes capable of simultaneous measurements. We anticipate that our innovative device will significantly improve the accessibility of neuroscience research.
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Affiliation(s)
- Haeyun Lee
- School
of Electronic and Electrical Engineering, College of IT Engineering, Kyungpook National University, Daegu 41566, Republic of Korea
| | - Seungbin Lee
- School
of Electronics Engineering, College of IT Engineering, Kyungpook National University, Daegu 41566, Republic of Korea
| | - Seungjun Lee
- Emotion,
Cognition & Behavior Research Group, Korea Brain Research Institute (KBRI), Daegu 41062, Republic of Korea
| | - Jimin Lee
- Emotion,
Cognition & Behavior Research Group, Korea Brain Research Institute (KBRI), Daegu 41062, Republic of Korea
| | - Namsun Chou
- Emotion,
Cognition & Behavior Research Group, Korea Brain Research Institute (KBRI), Daegu 41062, Republic of Korea
| | - Hyogeun Shin
- School
of Electronic and Electrical Engineering, College of IT Engineering, Kyungpook National University, Daegu 41566, Republic of Korea
- School
of Electronics Engineering, College of IT Engineering, Kyungpook National University, Daegu 41566, Republic of Korea
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3
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Ahmed Taha B, Addie AJ, Saeed AQ, Haider AJ, Chaudhary V, Arsad N. Nanostructured Photonics Probes: A Transformative Approach in Neurotherapeutics and Brain Circuitry. Neuroscience 2024; 562:106-124. [PMID: 39490518 DOI: 10.1016/j.neuroscience.2024.10.046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2024] [Revised: 10/23/2024] [Accepted: 10/24/2024] [Indexed: 11/05/2024]
Abstract
Neuroprobes that use nanostructured photonic interfaces are capable of multimodal sensing, stimulation, and imaging with unprecedented spatio-temporal resolution. In addition to electrical recording, optogenetic modulation, high-resolution optical imaging, and molecular sensing, these advanced probes combine nanophotonic waveguides, optical transducers, nanostructured electrodes, and biochemical sensors. The potential of this technology lies in unraveling the mysteries of neural coding principles, mapping functional connectivity in complex brain circuits, and developing new therapeutic interventions for neurological disorders. Nevertheless, achieving the full potential of nanostructured photonic neural probes requires overcoming challenges such as ensuring long-term biocompatibility, integrating nanoscale components at high density, and developing robust data-analysis pipelines. In this review, we summarize and discuss the role of photonics in neural probes, trends in electrode diameter for neural interface technologies, nanophotonic technologies using nanostructured materials, advances in nanofabrication photonics interface engineering, and challenges and opportunities. Finally, interdisciplinary efforts are required to unlock the transformative potential of next-generation neuroscience therapies.
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Affiliation(s)
- Bakr Ahmed Taha
- UKM-Department of Electrical, Electronic and Systems Engineering, Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia, UKM Bangi 43600, Malaysia.
| | - Ali J Addie
- Center of Industrial Applications and Materials Technology, Scientific Research Commission, Iraq
| | - Ali Q Saeed
- Computer Center / Northern Technical University, Iraq
| | - Adawiya J Haider
- Applied Sciences Department/Laser Science and Technology Branch, University of Technology, Iraq.
| | - Vishal Chaudhary
- Research Cell & Department of Physics, Bhagini Nivedita College, University of Delhi, New Delhi 110045, India; Centre for Research Impact & Outcome, Chitkara University, Punjab, 140401 India
| | - Norhana Arsad
- UKM-Department of Electrical, Electronic and Systems Engineering, Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia, UKM Bangi 43600, Malaysia.
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4
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Han J, Choi J, Jeong H, Park D, Cheong E, Sung J, Choi HJ. Impact of Impedance Levels on Recording Quality in Flexible Neural Probes. SENSORS (BASEL, SWITZERLAND) 2024; 24:2300. [PMID: 38610511 PMCID: PMC11014004 DOI: 10.3390/s24072300] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2024] [Revised: 04/01/2024] [Accepted: 04/03/2024] [Indexed: 04/14/2024]
Abstract
Flexible neural probes are attractive emerging technologies for brain recording because they can effectively record signals with minimal risk of brain damage. Reducing the electrode impedance of the probe before recording is a common practice of many researchers. However, studies investigating the impact of low impedance levels on high-quality recordings using flexible neural probes are lacking. In this study, we electrodeposited Pt onto a commercial flexible polyimide neural probe and investigated the relationship between the impedance level and the recording quality. The probe was inserted into the brains of anesthetized mice. The electrical signals of neurons in the brain, specifically the ventral posteromedial nucleus of the thalamus, were recorded at impedance levels of 50, 250, 500 and 1000 kΩ at 1 kHz. The study results demonstrated that as the impedance decreased, the quality of the signal recordings did not consistently improve. This suggests that extreme lowering of the impedance may not always be advantageous in the context of flexible neural probes.
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Affiliation(s)
- Juyeon Han
- Department of Materials Science and Engineering, Yonsei University, Seoul 03722, Republic of Korea; (J.H.)
| | - Jungsik Choi
- Department of Materials Science and Engineering, Yonsei University, Seoul 03722, Republic of Korea; (J.H.)
- Nformare Inc., Seodamun-gu, Seoul 03722, Republic of Korea
| | - Hyeonyeong Jeong
- Department of Biotechnology, Yonsei University, Seoul 03722, Republic of Korea
| | - Daerl Park
- Department of Materials Science and Engineering, Yonsei University, Seoul 03722, Republic of Korea; (J.H.)
| | - Eunji Cheong
- Department of Biotechnology, Yonsei University, Seoul 03722, Republic of Korea
| | - Jaesuk Sung
- Nformare Inc., Seodamun-gu, Seoul 03722, Republic of Korea
| | - Heon-Jin Choi
- Department of Materials Science and Engineering, Yonsei University, Seoul 03722, Republic of Korea; (J.H.)
- Nformare Inc., Seodamun-gu, Seoul 03722, Republic of Korea
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Faul EBA, Broussard AM, Rivera DR, Pwint MY, Wu B, Cao Q, Bailey D, Cui XT, Castagnola E. Batch Fabrication of Microelectrode Arrays with Glassy Carbon Microelectrodes and Interconnections for Neurochemical Sensing: Promises and Challenges. MICROMACHINES 2024; 15:277. [PMID: 38399004 PMCID: PMC10892456 DOI: 10.3390/mi15020277] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2024] [Revised: 02/07/2024] [Accepted: 02/13/2024] [Indexed: 02/25/2024]
Abstract
Flexible multielectrode arrays with glassy carbon (GC) electrodes and metal interconnection (hybrid MEAs) have shown promising performance in multi-channel neurochemical sensing. A primary challenge faced by hybrid MEAs fabrication is the adhesion of the metal traces with the GC electrodes, as prolonged electrical and mechanical stimulation can lead to adhesion failure. Previous devices with GC electrodes and interconnects made of a homogeneous material (all GC) demonstrated exceptional electrochemical stability but required miniaturization for enhanced tissue integration and chronic electrochemical sensing. In this study, we used two different methods for the fabrication of all GC-MEAs on thin flexible substrates with miniaturized features. The first method, like that previously reported, involves a double pattern-transfer photolithographic process, including transfer-bonding on temporary polymeric support. The second method requires a double-etching process, which uses a 2 µm-thick low stress silicon nitride coating of the Si wafer as the bottom insulator layer for the MEAs, bypassing the pattern-transfer and demonstrating a novel technique with potential advantages. We confirmed the feasibility of the two fabrication processes by verifying the practical conductivity of 3 µm-wide 2 µm-thick GC traces, the GC microelectrode functionality, and their sensing capability for the detection of serotonin using fast scan cyclic voltammetry. Through the exchange and discussion of insights regarding the strengths and limitations of these microfabrication methods, our goal is to propel the advancement of GC-based MEAs for the next generation of neural interface devices.
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Affiliation(s)
- Emma-Bernadette A. Faul
- Department of Biomedical Engineering, Louisiana Tech University, Ruston, LA 71272, USA; (E.-B.A.F.); (A.M.B.); (D.R.R.)
| | - Austin M. Broussard
- Department of Biomedical Engineering, Louisiana Tech University, Ruston, LA 71272, USA; (E.-B.A.F.); (A.M.B.); (D.R.R.)
| | - Daniel R. Rivera
- Department of Biomedical Engineering, Louisiana Tech University, Ruston, LA 71272, USA; (E.-B.A.F.); (A.M.B.); (D.R.R.)
| | - May Yoon Pwint
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15260, USA; (M.Y.P.); (B.W.); (Q.C.); (X.T.C.)
- Center for Neural Basis of Cognition, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Bingchen Wu
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15260, USA; (M.Y.P.); (B.W.); (Q.C.); (X.T.C.)
- Center for Neural Basis of Cognition, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Qun Cao
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15260, USA; (M.Y.P.); (B.W.); (Q.C.); (X.T.C.)
| | - Davis Bailey
- Institute for Micromanufacturing, Louisiana Tech University, Ruston, LA 15213, USA;
| | - X. Tracy Cui
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15260, USA; (M.Y.P.); (B.W.); (Q.C.); (X.T.C.)
- Center for Neural Basis of Cognition, University of Pittsburgh, Pittsburgh, PA 15261, USA
- McGowan Institute of Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA 15219-3110, USA
| | - Elisa Castagnola
- Department of Biomedical Engineering, Louisiana Tech University, Ruston, LA 71272, USA; (E.-B.A.F.); (A.M.B.); (D.R.R.)
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15260, USA; (M.Y.P.); (B.W.); (Q.C.); (X.T.C.)
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6
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Amirghasemi F, Soleimani A, Bawarith S, Tabassum A, Morrel A, Mousavi MPS. FAST (Flexible Acetylcholine Sensing Thread): Real-Time Detection of Acetylcholine with a Flexible Solid-Contact Potentiometric Sensor. Bioengineering (Basel) 2023; 10:655. [PMID: 37370586 DOI: 10.3390/bioengineering10060655] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Revised: 05/22/2023] [Accepted: 05/24/2023] [Indexed: 06/29/2023] Open
Abstract
Acetylcholine (ACh) is involved in memory and learning and has implications in neurodegenerative diseases; it is therefore important to study the dynamics of ACh in the brain. This work creates a flexible solid-contact potentiometric sensor for in vitro and in vivo recording of ACh in the brain and tissue homogenate. We fabricate this sensor using a 250 μm diameter cotton yarn coated with a flexible conductive ink and an ACh sensing membrane that contains a calix[4]arene ionophore. The exposed ion-to-electron transducer was sealed with a 2.5 μm thick Parylene C coating to maintain the flexibility of the sensor. The resulting diameter of the flexible ACh sensing thread (FAST) was 400 μm. The FAST showed a linear response range from 1.0 μM to 10.0 mM in deionized water, with a near-Nernstian slope of 56.11 mV/decade and a limit of detection of 2.6 μM. In artificial cerebrospinal fluid, the limit of detection increased to 20 μM due to the background signal of ionic content of the cerebrospinal fluid. The FAST showed a signal stability of 226 μV/h over 24 h. We show that FAST can measure ACh dynamics in sheep brain tissue and sheep brain homogenate after ACh spiking. FAST is the first flexible electrochemical sensor for monitoring ACh dynamics in the brain.
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Affiliation(s)
- Farbod Amirghasemi
- Alfred E. Mann Department of Biomedical Engineering, Viterbi School of Engineering, University of Southern California, Los Angeles, CA 90089, USA
| | - Ali Soleimani
- Alfred E. Mann Department of Biomedical Engineering, Viterbi School of Engineering, University of Southern California, Los Angeles, CA 90089, USA
| | - Shahd Bawarith
- Alfred E. Mann Department of Biomedical Engineering, Viterbi School of Engineering, University of Southern California, Los Angeles, CA 90089, USA
| | - Asna Tabassum
- Alfred E. Mann Department of Biomedical Engineering, Viterbi School of Engineering, University of Southern California, Los Angeles, CA 90089, USA
| | - Alayne Morrel
- Alfred E. Mann Department of Biomedical Engineering, Viterbi School of Engineering, University of Southern California, Los Angeles, CA 90089, USA
| | - Maral P S Mousavi
- Alfred E. Mann Department of Biomedical Engineering, Viterbi School of Engineering, University of Southern California, Los Angeles, CA 90089, USA
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Letner JG, Patel PR, Hsieh JC, Smith Flores IM, della Valle E, Walker LA, Weiland JD, Chestek CA, Cai D. Post-explant profiling of subcellular-scale carbon fiber intracortical electrodes and surrounding neurons enables modeling of recorded electrophysiology. J Neural Eng 2023; 20:026019. [PMID: 36848679 PMCID: PMC10022369 DOI: 10.1088/1741-2552/acbf78] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 01/12/2023] [Accepted: 02/27/2023] [Indexed: 03/01/2023]
Abstract
Objective.Characterizing the relationship between neuron spiking and the signals that electrodes record is vital to defining the neural circuits driving brain function and informing clinical brain-machine interface design. However, high electrode biocompatibility and precisely localizing neurons around the electrodes are critical to defining this relationship.Approach.Here, we demonstrate consistent localization of the recording site tips of subcellular-scale (6.8µm diameter) carbon fiber electrodes and the positions of surrounding neurons. We implanted male rats with carbon fiber electrode arrays for 6 or 12+ weeks targeting layer V motor cortex. After explanting the arrays, we immunostained the implant site and localized putative recording site tips with subcellular-cellular resolution. We then 3D segmented neuron somata within a 50µm radius from implanted tips to measure neuron positions and health and compare to healthy cortex with symmetric stereotaxic coordinates.Main results.Immunostaining of astrocyte, microglia, and neuron markers confirmed that overall tissue health was indicative of high biocompatibility near the tips. While neurons near implanted carbon fibers were stretched, their number and distribution were similar to hypothetical fibers placed in healthy contralateral brain. Such similar neuron distributions suggest that these minimally invasive electrodes demonstrate the potential to sample naturalistic neural populations. This motivated the prediction of spikes produced by nearby neurons using a simple point source model fit using recorded electrophysiology and the mean positions of the nearest neurons observed in histology. Comparing spike amplitudes suggests that the radius at which single units can be distinguished from others is near the fourth closest neuron (30.7 ± 4.6µm,X-± S) in layer V motor cortex.Significance.Collectively, these data and simulations provide the first direct evidence that neuron placement in the immediate vicinity of the recording site influences how many spike clusters can be reliably identified by spike sorting.
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Affiliation(s)
- Joseph G Letner
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, United States of America
- Biointerfaces Institute, University of Michigan, Ann Arbor, MI 48109, United States of America
| | - Paras R Patel
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, United States of America
- Biointerfaces Institute, University of Michigan, Ann Arbor, MI 48109, United States of America
| | - Jung-Chien Hsieh
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI 48109, United States of America
| | - Israel M Smith Flores
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, United States of America
- Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, MI 48109, United States of America
| | - Elena della Valle
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, United States of America
- Biointerfaces Institute, University of Michigan, Ann Arbor, MI 48109, United States of America
| | - Logan A Walker
- Biophysics Program, University of Michigan, Ann Arbor, MI 48109, United States of America
- Department of Computational Medicine and Bioinformatics, Michigan Medicine, Ann Arbor, MI 48109, United States of America
| | - James D Weiland
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, United States of America
- Biointerfaces Institute, University of Michigan, Ann Arbor, MI 48109, United States of America
- Department of Ophthalmology and Visual Sciences, Kellogg Eye Center, University of Michigan, Ann Arbor, MI 48105, United States of America
| | - Cynthia A Chestek
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, United States of America
- Biointerfaces Institute, University of Michigan, Ann Arbor, MI 48109, United States of America
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI 48109, United States of America
- Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, MI 48109, United States of America
- Robotics Department, University of Michigan, Ann Arbor, MI 48109, United States of America
| | - Dawen Cai
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI 48109, United States of America
- Biophysics Program, University of Michigan, Ann Arbor, MI 48109, United States of America
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI 48109, United States of America
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Sensing and Stimulation Applications of Carbon Nanomaterials in Implantable Brain-Computer Interface. Int J Mol Sci 2023; 24:ijms24065182. [PMID: 36982255 PMCID: PMC10048878 DOI: 10.3390/ijms24065182] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2022] [Revised: 02/23/2023] [Accepted: 02/28/2023] [Indexed: 03/11/2023] Open
Abstract
Implantable brain–computer interfaces (BCIs) are crucial tools for translating basic neuroscience concepts into clinical disease diagnosis and therapy. Among the various components of the technological chain that increases the sensing and stimulation functions of implanted BCI, the interface materials play a critical role. Carbon nanomaterials, with their superior electrical, structural, chemical, and biological capabilities, have become increasingly popular in this field. They have contributed significantly to advancing BCIs by improving the sensor signal quality of electrical and chemical signals, enhancing the impedance and stability of stimulating electrodes, and precisely modulating neural function or inhibiting inflammatory responses through drug release. This comprehensive review provides an overview of carbon nanomaterials’ contributions to the field of BCI and discusses their potential applications. The topic is broadened to include the use of such materials in the field of bioelectronic interfaces, as well as the potential challenges that may arise in future implantable BCI research and development. By exploring these issues, this review aims to provide insight into the exciting developments and opportunities that lie ahead in this rapidly evolving field.
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Li SY, Tseng HY, Chen BW, Lo YC, Shao HH, Wu YT, Li SJ, Chang CW, Liu TC, Hsieh FY, Yang Y, Lai YB, Chen PC, Chen YY. Proof of Concept for Sustainable Manufacturing of Neural Electrode Array for In Vivo Recording. BIOSENSORS 2023; 13:280. [PMID: 36832046 PMCID: PMC9953957 DOI: 10.3390/bios13020280] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 02/01/2023] [Accepted: 02/13/2023] [Indexed: 06/18/2023]
Abstract
Increasing requirements for neural implantation are helping to expand our understanding of nervous systems and generate new developmental approaches. It is thanks to advanced semiconductor technologies that we can achieve the high-density complementary metal-oxide-semiconductor electrode array for the improvement of the quantity and quality of neural recordings. Although the microfabricated neural implantable device holds much promise in the biosensing field, there are some significant technological challenges. The most advanced neural implantable device relies on complex semiconductor manufacturing processes, which are required for the use of expensive masks and specific clean room facilities. In addition, these processes based on a conventional photolithography technique are suitable for mass production, which is not applicable for custom-made manufacturing in response to individual experimental requirements. The microfabricated complexity of the implantable neural device is increasing, as is the associated energy consumption, and corresponding emissions of carbon dioxide and other greenhouse gases, resulting in environmental deterioration. Herein, we developed a fabless fabricated process for a neural electrode array that was simple, fast, sustainable, and customizable. An effective strategy to produce conductive patterns as the redistribution layers (RDLs) includes implementing microelectrodes, traces, and bonding pads onto the polyimide (PI) substrate by laser micromachining techniques combined with the drop coating of the silver glue to stack the laser grooving lines. The process of electroplating platinum on the RDLs was performed to increase corresponding conductivity. Sequentially, Parylene C was deposited onto the PI substrate to form the insulation layer for the protection of inner RDLs. Following the deposition of Parylene C, the via holes over microelectrodes and the corresponding probe shape of the neural electrode array was also etched by laser micromachining. To increase the neural recording capability, three-dimensional microelectrodes with a high surface area were formed by electroplating gold. Our eco-electrode array showed reliable electrical characteristics of impedance under harsh cyclic bending conditions of over 90 degrees. For in vivo application, our flexible neural electrode array demonstrated more stable and higher neural recording quality and better biocompatibility as well during the 2-week implantation compared with those of the silicon-based neural electrode array. In this study, our proposed eco-manufacturing process for fabricating the neural electrode array reduced 63 times of carbon emissions compared to the traditional semiconductor manufacturing process and provided freedom in the customized design of the implantable electronic devices as well.
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Affiliation(s)
- Szu-Ying Li
- Department of Biomedical Engineering, National Yang Ming Chiao Tung University, No.155, Sec. 2, Linong St., Taipei 112304, Taiwan
| | - Hsin-Yi Tseng
- The Ph.D. Program in Medical Neuroscience, College of Medical Science and Technology, Taipei Medical University, No. 250 Wu-Xing St., Taipei 11031, Taiwan
| | - Bo-Wei Chen
- Department of Biomedical Engineering, National Yang Ming Chiao Tung University, No.155, Sec. 2, Linong St., Taipei 112304, Taiwan
| | - Yu-Chun Lo
- The Ph.D. Program in Medical Neuroscience, College of Medical Science and Technology, Taipei Medical University, No. 250 Wu-Xing St., Taipei 11031, Taiwan
| | - Huai-Hsuan Shao
- Department of Biomedical Engineering, National Yang Ming Chiao Tung University, No.155, Sec. 2, Linong St., Taipei 112304, Taiwan
| | - Yen-Ting Wu
- Department of Biomedical Engineering, National Yang Ming Chiao Tung University, No.155, Sec. 2, Linong St., Taipei 112304, Taiwan
| | - Ssu-Ju Li
- Department of Biomedical Engineering, National Yang Ming Chiao Tung University, No.155, Sec. 2, Linong St., Taipei 112304, Taiwan
| | - Ching-Wen Chang
- Department of Biomedical Engineering, National Yang Ming Chiao Tung University, No.155, Sec. 2, Linong St., Taipei 112304, Taiwan
| | - Ta-Chung Liu
- Department of Biomedical Engineering, National Yang Ming Chiao Tung University, No.155, Sec. 2, Linong St., Taipei 112304, Taiwan
| | - Fu-Yu Hsieh
- Franz Collection Inc., 13F, No. 167, Sec. 5, Ming Sheng E. Rd., Taipei 10589, Taiwan
| | - Yi Yang
- Department of Biomedical Engineering, Johns Hopkins University, No. 720 Rutland Ave., Baltimore, MD 21205, USA
| | - Yan-Bo Lai
- Department of Materials and Mineral Resources Engineering, National Taipei University of Technology, No. 1, Sec. 3, Zhongxiao E. Rd., Taipei 10608, Taiwan
| | - Po-Chun Chen
- Department of Materials and Mineral Resources Engineering, National Taipei University of Technology, No. 1, Sec. 3, Zhongxiao E. Rd., Taipei 10608, Taiwan
| | - You-Yin Chen
- Department of Biomedical Engineering, National Yang Ming Chiao Tung University, No.155, Sec. 2, Linong St., Taipei 112304, Taiwan
- Franz Collection Inc., 13F, No. 167, Sec. 5, Ming Sheng E. Rd., Taipei 10589, Taiwan
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10
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Saalmann YB, Mofakham S, Mikell CB, Djuric PM. Microscale multicircuit brain stimulation: Achieving real-time brain state control for novel applications. CURRENT RESEARCH IN NEUROBIOLOGY 2022; 4:100071. [PMID: 36619175 PMCID: PMC9816916 DOI: 10.1016/j.crneur.2022.100071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Revised: 11/30/2022] [Accepted: 12/19/2022] [Indexed: 12/30/2022] Open
Abstract
Neurological and psychiatric disorders typically result from dysfunction across multiple neural circuits. Most of these disorders lack a satisfactory neuromodulation treatment. However, deep brain stimulation (DBS) has been successful in a limited number of disorders; DBS typically targets one or two brain areas with single contacts on relatively large electrodes, allowing for only coarse modulation of circuit function. Because of the dysfunction in distributed neural circuits - each requiring fine, tailored modulation - that characterizes most neuropsychiatric disorders, this approach holds limited promise. To develop the next generation of neuromodulation therapies, we will have to achieve fine-grained, closed-loop control over multiple neural circuits. Recent work has demonstrated spatial and frequency selectivity using microstimulation with many small, closely-spaced contacts, mimicking endogenous neural dynamics. Using custom electrode design and stimulation parameters, it should be possible to achieve bidirectional control over behavioral outcomes, such as increasing or decreasing arousal during central thalamic stimulation. Here, we discuss one possible approach, which we term microscale multicircuit brain stimulation (MMBS). We discuss how machine learning leverages behavioral and neural data to find optimal stimulation parameters across multiple contacts, to drive the brain towards desired states associated with behavioral goals. We expound a mathematical framework for MMBS, where behavioral and neural responses adjust the model in real-time, allowing us to adjust stimulation in real-time. These technologies will be critical to the development of the next generation of neurostimulation therapies, which will allow us to treat problems like disorders of consciousness and cognition.
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Affiliation(s)
- Yuri B. Saalmann
- Department of Psychology, University of Wisconsin-Madison, Madison, WI, USA
- Wisconsin National Primate Research Center, University of Wisconsin-Madison, Madison, WI, USA
| | - Sima Mofakham
- Department of Neurological Surgery, Stony Brook University Hospital, Stony Brook, NY, USA
- Department of Electrical and Computer Engineering, Stony Brook University, Stony Brook, NY, USA
| | - Charles B. Mikell
- Department of Neurological Surgery, Stony Brook University Hospital, Stony Brook, NY, USA
| | - Petar M. Djuric
- Department of Electrical and Computer Engineering, Stony Brook University, Stony Brook, NY, USA
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11
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Guo Z, Wang F, Wang L, Tu K, Jiang C, Xi Y, Hong W, Xu Q, Wang X, Yang B, Sun B, Lin Z, Liu J. A flexible neural implant with ultrathin substrate for low-invasive brain-computer interface applications. MICROSYSTEMS & NANOENGINEERING 2022; 8:133. [PMID: 36575664 PMCID: PMC9789992 DOI: 10.1038/s41378-022-00464-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Revised: 06/03/2022] [Accepted: 06/30/2022] [Indexed: 06/17/2023]
Abstract
Implantable brain-computer interface (BCI) devices are an effective tool to decipher fundamental brain mechanisms and treat neural diseases. However, traditional neural implants with rigid or bulky cross-sections cause trauma and decrease the quality of the neuronal signal. Here, we propose a MEMS-fabricated flexible interface device for BCI applications. The microdevice with a thin film substrate can be readily reduced to submicron scale for low-invasive implantation. An elaborate silicon shuttle with an improved structure is designed to reliably implant the flexible device into brain tissue. The flexible substrate is temporarily bonded to the silicon shuttle by polyethylene glycol. On the flexible substrate, eight electrodes with different diameters are distributed evenly for local field potential and neural spike recording, both of which are modified by Pt-black to enhance the charge storage capacity and reduce the impedance. The mechanical and electrochemical characteristics of this interface were investigated in vitro. In vivo, the small cross-section of the device promises reduced trauma, and the neuronal signals can still be recorded one month after implantation, demonstrating the promise of this kind of flexible BCI device as a low-invasive tool for brain-computer communication.
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Affiliation(s)
- Zhejun Guo
- National Key Laboratory of Science and Technology on Micro/Nano Fabrication, Shanghai Jiao Tong University, 200240 Shanghai, China
- Department of Micro/Nano Electronics, Shanghai Jiao Tong University, 200240 Shanghai, China
| | - Fang Wang
- Department of Neurosurgery, Center for Functional Neurosurgery, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, 200025 Shanghai, China
| | - Longchun Wang
- National Key Laboratory of Science and Technology on Micro/Nano Fabrication, Shanghai Jiao Tong University, 200240 Shanghai, China
- Department of Micro/Nano Electronics, Shanghai Jiao Tong University, 200240 Shanghai, China
| | - Kejun Tu
- National Key Laboratory of Science and Technology on Micro/Nano Fabrication, Shanghai Jiao Tong University, 200240 Shanghai, China
- Department of Micro/Nano Electronics, Shanghai Jiao Tong University, 200240 Shanghai, China
| | - Chunpeng Jiang
- National Key Laboratory of Science and Technology on Micro/Nano Fabrication, Shanghai Jiao Tong University, 200240 Shanghai, China
- Department of Micro/Nano Electronics, Shanghai Jiao Tong University, 200240 Shanghai, China
| | - Ye Xi
- National Key Laboratory of Science and Technology on Micro/Nano Fabrication, Shanghai Jiao Tong University, 200240 Shanghai, China
- Department of Micro/Nano Electronics, Shanghai Jiao Tong University, 200240 Shanghai, China
| | - Wen Hong
- National Key Laboratory of Science and Technology on Micro/Nano Fabrication, Shanghai Jiao Tong University, 200240 Shanghai, China
- Department of Micro/Nano Electronics, Shanghai Jiao Tong University, 200240 Shanghai, China
| | - Qingda Xu
- National Key Laboratory of Science and Technology on Micro/Nano Fabrication, Shanghai Jiao Tong University, 200240 Shanghai, China
- Department of Micro/Nano Electronics, Shanghai Jiao Tong University, 200240 Shanghai, China
| | - Xiaolin Wang
- National Key Laboratory of Science and Technology on Micro/Nano Fabrication, Shanghai Jiao Tong University, 200240 Shanghai, China
| | - Bin Yang
- National Key Laboratory of Science and Technology on Micro/Nano Fabrication, Shanghai Jiao Tong University, 200240 Shanghai, China
| | - Bomin Sun
- Department of Neurosurgery, Center for Functional Neurosurgery, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, 200025 Shanghai, China
| | - Zude Lin
- National Key Laboratory of Science and Technology on Micro/Nano Fabrication, Shanghai Jiao Tong University, 200240 Shanghai, China
| | - Jingquan Liu
- National Key Laboratory of Science and Technology on Micro/Nano Fabrication, Shanghai Jiao Tong University, 200240 Shanghai, China
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12
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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: 2.3] [Reference Citation Analysis] [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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13
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Lotfi Marchoubeh M, Cobb SJ, Abrego Tello M, Hu M, Jaquins-Gerstl A, Robbins EM, Macpherson JV, Michael AC, Fritsch I. Miniaturized probe on polymer SU-8 with array of individually addressable microelectrodes for electrochemical analysis in neural and other biological tissues. Anal Bioanal Chem 2021; 413:6777-6791. [PMID: 33961102 DOI: 10.1007/s00216-021-03327-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Revised: 03/15/2021] [Accepted: 04/01/2021] [Indexed: 01/08/2023]
Abstract
An SU-8 probe with an array of nine, individually addressable gold microband electrodes (100 μm long, 4 μm wide, separated by 4-μm gaps) was photolithographically fabricated and characterized for detection of low concentrations of chemicals in confined spaces and in vivo studies of biological tissues. The probe's shank (6 mm long, 100 μm wide, 100 μm thick) is flexible, but exhibits sufficient sharpness and rigidity to be inserted into soft tissue. Laser micromachining was used to define probe geometry by spatially revealing the underlying sacrificial aluminum layer, which was then etched to free the probes from a silicon wafer. Perfusion with fluorescent nanobeads showed that, like a carbon fiber electrode, the probe produced no noticeable damage when inserted into rat brain, in contrast to damage from an inserted microdialysis probe. The individual addressability of the electrodes allows single and multiple electrode activation. Redox cycling is possible, where adjacent electrodes serve as generators (that oxidize or reduce molecules) and collectors (that do the opposite) to amplify signals of small concentrations without background subtraction. Information about electrochemical mechanisms and kinetics may also be obtained. Detection limits for potassium ferricyanide in potassium chloride electrolyte of 2.19, 1.25, and 2.08 μM and for dopamine in artificial cerebral spinal fluid of 1.94, 1.08, and 5.66 μM for generators alone and for generators and collectors during redox cycling, respectively, were obtained.
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Affiliation(s)
- Mahsa Lotfi Marchoubeh
- Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, AR, 72701, USA
| | - Samuel J Cobb
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK
- Department of Chemistry and Centre for Doctoral Training in Diamond Science and Technology, and Department of Physics, University of Warwick, Coventry, UK
| | - Miguel Abrego Tello
- Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, AR, 72701, USA
| | - Mengjia Hu
- Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, AR, 72701, USA
| | | | - Elaine M Robbins
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA, 15260, USA
| | - Julie V Macpherson
- Department of Chemistry and Centre for Doctoral Training in Diamond Science and Technology, and Department of Physics, University of Warwick, Coventry, UK
| | - Adrian C Michael
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA, 15260, USA
| | - Ingrid Fritsch
- Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, AR, 72701, USA.
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14
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Faraji Rad Z, Prewett PD, Davies GJ. An overview of microneedle applications, materials, and fabrication methods. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2021; 12:1034-1046. [PMID: 34621614 PMCID: PMC8450954 DOI: 10.3762/bjnano.12.77] [Citation(s) in RCA: 80] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Accepted: 08/30/2021] [Indexed: 05/19/2023]
Abstract
Microneedle-based microdevices promise to expand the scope for delivery of vaccines and therapeutic agents through the skin and withdrawing biofluids for point-of-care diagnostics - so-called theranostics. Unskilled and painless applications of microneedle patches for blood collection or drug delivery are two of the advantages of microneedle arrays over hypodermic needles. Developing the necessary microneedle fabrication processes has the potential to dramatically impact the health care delivery system by changing the landscape of fluid sampling and subcutaneous drug delivery. Microneedle designs which range from sub-micron to millimetre feature sizes are fabricated using the tools of the microelectronics industry from metals, silicon, and polymers. Various types of subtractive and additive manufacturing processes have been used to manufacture microneedles, but the development of microneedle-based systems using conventional subtractive methods has been constrained by the limitations and high cost of microfabrication technology. Additive manufacturing processes such as 3D printing and two-photon polymerization fabrication are promising transformative technologies developed in recent years. The present article provides an overview of microneedle systems applications, designs, material selection, and manufacturing methods.
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Affiliation(s)
- Zahra Faraji Rad
- School of Mechanical and Electrical Engineering, University of Southern Queensland, Springfield Central, QLD 4300, Australia
| | - Philip D Prewett
- Department of Mechanical Engineering, University of Birmingham, Birmingham B15 2TT, United Kingdom
- Oxacus Ltd, Dorchester-on-Thames, OX10 7HN, United Kingdom
| | - Graham J Davies
- Faculty of Engineering, UNSW Australia, NSW 2052, Australia
- College of Engineering & Physical Sciences, School of Engineering, University of Birmingham, Birmingham, B15 2TT, United Kingdom
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15
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Abstract
The recent advances in bio-integratable electronics are creating new opportunities for investigating and directing biologically significant processes, yet their performance to date is still limited by the inherent physiochemical and signaling mismatches at the heterogeneous interfaces. Hydrogels represent a unique category of materials to bridge the gap between biological and electronic systems because of their structural/functional similarity to biological tissues and design versatility to accommodate cross-system communication. In this review, we discuss the latest progress in the engineering of hydrogel interfaces for bioelectronics development that promotes (1) structural compatibility, where the mechanical and chemical properties of hydrogels can be modulated to achieve coherent, chronically stable biotic-abiotic junctions; and (2) interfacial signal transduction, where the charge and mass transport within the hydrogel mediators can be rationally programmed to condition/amplify the bioderived signals and enhance the electrical/electrochemical coupling. We will further discuss the application of functional hydrogels in complex physiological environments for bioelectronic integration across different scales/biological levels. These ongoing research efforts have the potential to blur the distinction between living systems and artificial electronics, and ultimately decode and regulate biological functioning for both fundamental inquiries and biomedical applications.
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Affiliation(s)
- Richard Vo
- Department of Biomedical Engineering, Tufts University, Medford, MA 02155, USA.
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16
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McGlynn E, Nabaei V, Ren E, Galeote‐Checa G, Das R, Curia G, Heidari H. The Future of Neuroscience: Flexible and Wireless Implantable Neural Electronics. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2021; 8:2002693. [PMID: 34026431 PMCID: PMC8132070 DOI: 10.1002/advs.202002693] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 01/15/2021] [Indexed: 05/04/2023]
Abstract
Neurological diseases are a prevalent cause of global mortality and are of growing concern when considering an ageing global population. Traditional treatments are accompanied by serious side effects including repeated treatment sessions, invasive surgeries, or infections. For example, in the case of deep brain stimulation, large, stiff, and battery powered neural probes recruit thousands of neurons with each pulse, and can invoke a vigorous immune response. This paper presents challenges in engineering and neuroscience in developing miniaturized and biointegrated alternatives, in the form of microelectrode probes. Progress in design and topology of neural implants has shifted the goal post toward highly specific recording and stimulation, targeting small groups of neurons and reducing the foreign body response with biomimetic design principles. Implantable device design recommendations, fabrication techniques, and clinical evaluation of the impact flexible, integrated probes will have on the treatment of neurological disorders are provided in this report. The choice of biocompatible material dictates fabrication techniques as novel methods reduce the complexity of manufacture. Wireless power, the final hurdle to truly implantable neural interfaces, is discussed. These aspects are the driving force behind continued research: significant breakthroughs in any one of these areas will revolutionize the treatment of neurological disorders.
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Affiliation(s)
- Eve McGlynn
- Microelectronics LabJames Watt School of EngineeringUniversity of GlasgowGlasgowG12 8QQUnited Kingdom
| | - Vahid Nabaei
- Microelectronics LabJames Watt School of EngineeringUniversity of GlasgowGlasgowG12 8QQUnited Kingdom
| | - Elisa Ren
- Laboratory of Experimental Electroencephalography and NeurophysiologyDepartment of BiomedicalMetabolic and Neural SciencesUniversity of Modena and Reggio EmiliaModena41125Italy
| | - Gabriel Galeote‐Checa
- Microelectronics LabJames Watt School of EngineeringUniversity of GlasgowGlasgowG12 8QQUnited Kingdom
| | - Rupam Das
- Microelectronics LabJames Watt School of EngineeringUniversity of GlasgowGlasgowG12 8QQUnited Kingdom
| | - Giulia Curia
- Laboratory of Experimental Electroencephalography and NeurophysiologyDepartment of BiomedicalMetabolic and Neural SciencesUniversity of Modena and Reggio EmiliaModena41125Italy
| | - Hadi Heidari
- Microelectronics LabJames Watt School of EngineeringUniversity of GlasgowGlasgowG12 8QQUnited Kingdom
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17
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Abstract
When nerves are damaged by trauma or disease, they are still capable of firing off electrical command signals that originate from the brain. Furthermore, those damaged nerves have an innate ability to partially regenerate, so they can heal from trauma and even reinnervate new muscle targets. For an amputee who has his/her damaged nerves surgically reconstructed, the electrical signals that are generated by the reinnervated muscle tissue can be sensed and interpreted with bioelectronics to control assistive devices or robotic prostheses. No two amputees will have identical physiologies because there are many surgical options for reconstructing residual limbs, which may in turn impact how well someone can interface with a robotic prosthesis later on. In this review, we aim to investigate what the literature has to say about different pathways for peripheral nerve regeneration and how each pathway can impact the neuromuscular tissue’s final electrophysiology. This information is important because it can guide us in planning the development of future bioelectronic devices, such as prosthetic limbs or neurostimulators. Future devices will primarily have to interface with tissue that has undergone some natural regeneration process, and so we have explored and reported here what is known about the bioelectrical features of neuromuscular tissue regeneration.
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18
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Chong H, Majerus SJ, Bogie KM, Zorman CA. Non‐hermetic packaging of biomedical microsystems from a materials perspective: A review. ACTA ACUST UNITED AC 2020. [DOI: 10.1002/mds3.10082] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Hao Chong
- Department of Electrical, Computer, and Systems Engineering Case Western Reserve University Cleveland OH USA
| | | | - Kath M. Bogie
- APT Center Louis Stokes VA Medical Center Cleveland OH USA
- Department of Orthopaedics Case Western Reserve University School of Medicine Cleveland OH USA
| | - Christian A. Zorman
- Department of Electrical, Computer, and Systems Engineering Case Western Reserve University Cleveland OH USA
- APT Center Louis Stokes VA Medical Center Cleveland OH USA
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19
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Jung YH, Kim JU, Lee JS, Shin JH, Jung W, Ok J, Kim TI. Injectable Biomedical Devices for Sensing and Stimulating Internal Body Organs. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2020; 32:e1907478. [PMID: 32104960 DOI: 10.1002/adma.201907478] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Revised: 01/15/2020] [Indexed: 06/10/2023]
Abstract
The rapid pace of progress in implantable electronics driven by novel technology has created devices with unconventional designs and features to reduce invasiveness and establish new sensing and stimulating techniques. Among the designs, injectable forms of biomedical electronics are explored for accurate and safe targeting of deep-seated body organs. Here, the classes of biomedical electronics and tools that have high aspect ratio structures designed to be injected or inserted into internal organs for minimally invasive monitoring and therapy are reviewed. Compared with devices in bulky or planar formats, the long shaft-like forms of implantable devices are easily placed in the organs with minimized outward protrusions via injection or insertion processes. Adding flexibility to the devices also enables effortless insertions through complex biological cavities, such as the cochlea, and enhances chronic reliability by complying with natural body movements, such as the heartbeat. Diverse types of such injectable implants developed for different organs are reviewed and the electronic, optoelectronic, piezoelectric, and microfluidic devices that enable stimulations and measurements of site-specific regions in the body are discussed. Noninvasive penetration strategies to deliver the miniscule devices are also considered. Finally, the challenges and future directions associated with deep body biomedical electronics are explained.
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Affiliation(s)
- Yei Hwan Jung
- School of Chemical Engineering, Sungkyunkwan University (SKKU), Suwon, 16419, Republic of Korea
| | - Jong Uk Kim
- School of Chemical Engineering, Sungkyunkwan University (SKKU), Suwon, 16419, Republic of Korea
| | - Ju Seung Lee
- School of Chemical Engineering, Sungkyunkwan University (SKKU), Suwon, 16419, Republic of Korea
| | - Joo Hwan Shin
- School of Chemical Engineering, Sungkyunkwan University (SKKU), Suwon, 16419, Republic of Korea
| | - Woojin Jung
- School of Chemical Engineering, Sungkyunkwan University (SKKU), Suwon, 16419, Republic of Korea
| | - Jehyung Ok
- School of Chemical Engineering, Sungkyunkwan University (SKKU), Suwon, 16419, Republic of Korea
| | - Tae-Il Kim
- School of Chemical Engineering, Department of Biomedical Engineering, and Biomedical Institute for Convergence at SKKU (BICS), Sungkyunkwan University (SKKU), Suwon, 16419, Republic of Korea
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20
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Obidin N, Tasnim F, Dagdeviren C. The Future of Neuroimplantable Devices: A Materials Science and Regulatory Perspective. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2020; 32:e1901482. [PMID: 31206827 DOI: 10.1002/adma.201901482] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Revised: 04/12/2019] [Indexed: 06/09/2023]
Abstract
The past two decades have seen unprecedented progress in the development of novel materials, form factors, and functionalities in neuroimplantable technologies, including electrocorticography (ECoG) systems, multielectrode arrays (MEAs), Stentrode, and deep brain probes. The key considerations for the development of such devices intended for acute implantation and chronic use, from the perspective of biocompatible hybrid materials incorporation, conformable device design, implantation procedures, and mechanical and biological risk factors, are highlighted. These topics are connected with the role that the U.S. Food and Drug Administration (FDA) plays in its regulation of neuroimplantable technologies based on the above parameters. Existing neuroimplantable devices and efforts to improve their materials and implantation protocols are first discussed in detail. The effects of device implantation with regards to biocompatibility and brain heterogeneity are then explored. Topics examined include brain-specific risk factors, such as bacterial infection, tissue scarring, inflammation, and vasculature damage, as well as efforts to manage these dangers through emerging hybrid, bioelectronic device architectures. The current challenges of gaining clinical approval by the FDA-in particular, with regards to biological, mechanical, and materials risk factors-are summarized. The available regulatory pathways to accelerate next-generation neuroimplantable devices to market are then discussed.
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Affiliation(s)
- Nikita Obidin
- MIT Media Lab, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Farita Tasnim
- MIT Media Lab, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Canan Dagdeviren
- MIT Media Lab, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
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21
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El-Atab N, Shaikh SF, Hussain MM. Nano-scale transistors for interfacing with brain: design criteria, progress and prospect. NANOTECHNOLOGY 2019; 30:442001. [PMID: 31342924 DOI: 10.1088/1361-6528/ab3534] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
According to the World Health Organization, one quarter of the world's population suffers from various neurological disorders ranging from depression to Alzheimer's disease. Thus, understanding the operation mechanism of the brain enables us to help those who are suffering from these diseases. In addition, recent clinical medicine employs electronic brain implants, despite the fact of being invasive, to treat disorders ranging from severe coronary conditions to traumatic injuries. As a result, the deaf could hear, the blind could see, and the paralyzed could control robotic arms and legs. Due to the requirement of high data management capability with a power consumption as low as possible, designing nanoscale transistors as essential I/O electronics is a complex task. Herein, we review the essential design criteria for such nanoscale transistors, progress and prospect for implantable brain-machine-interface electronics. This article also discusses their technological challenges for practical implementation.
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Affiliation(s)
- Nazek El-Atab
- MMH Labs, Computer Electrical Mathematical Science and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia
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22
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Kim C, Jeong J, Kim SJ. Recent Progress on Non-Conventional Microfabricated Probes for the Chronic Recording of Cortical Neural Activity. SENSORS (BASEL, SWITZERLAND) 2019; 19:E1069. [PMID: 30832357 PMCID: PMC6427797 DOI: 10.3390/s19051069] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Revised: 02/25/2019] [Accepted: 02/26/2019] [Indexed: 02/06/2023]
Abstract
Microfabrication technology for cortical interfaces has advanced rapidly over the past few decades for electrophysiological studies and neuroprosthetic devices offering the precise recording and stimulation of neural activity in the cortex. While various cortical microelectrode arrays have been extensively and successfully demonstrated in animal and clinical studies, there remains room for further improvement of the probe structure, materials, and fabrication technology, particularly for high-fidelity recording in chronic implantation. A variety of non-conventional probes featuring unique characteristics in their designs, materials and fabrication methods have been proposed to address the limitations of the conventional standard shank-type ("Utah-" or "Michigan-" type) devices. Such non-conventional probes include multi-sided arrays to avoid shielding and increase recording volumes, mesh- or thread-like arrays for minimized glial scarring and immune response, tube-type or cylindrical probes for three-dimensional (3D) recording and multi-modality, folded arrays for high conformability and 3D recording, self-softening or self-deployable probes for minimized tissue damage and extensions of the recording sites beyond gliosis, nanostructured probes to reduce the immune response, and cone-shaped electrodes for promoting tissue ingrowth and long-term recording stability. Herein, the recent progress with reference to the many different types of non-conventional arrays is reviewed while highlighting the challenges to be addressed and the microfabrication techniques necessary to implement such features.
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Affiliation(s)
- Chaebin Kim
- Department of Electrical and Computer Engineering, Seoul National University, Seoul 08826, Korea.
| | - Joonsoo Jeong
- Department of Biomedical Engineering, School of Medicine, Pusan National University, Yangsan 50612, Korea.
| | - Sung June Kim
- Department of Electrical and Computer Engineering, Seoul National University, Seoul 08826, Korea.
- Institute on Aging, College of Medicine, Seoul National University, Seoul 08826, Korea.
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23
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Cramer SD, Lee JS, Butt MT, Paulin J, Stoffregen WC. Neurologic Medical Device Overview for Pathologists. Toxicol Pathol 2019; 47:250-263. [PMID: 30599801 DOI: 10.1177/0192623318816685] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Thorough morphologic evaluations of medical devices placed in or near the nervous system depend on many factors. Pathologists interpreting a neurologic device study must be familiar with the regulatory framework affecting device development, biocompatibility and safety determinants impacting nervous tissue responses, and appropriate study design, including the use of appropriate animal models, group design, device localization, euthanasia time points, tissue examination, sampling and processing, histochemistry and immunohistochemistry, and reporting. This overview contextualizes these features of neurologic medical devices for pathologists engaged in device evaluations.
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Affiliation(s)
| | | | - Mark T Butt
- 1 Tox Path Specialists, LLC, Frederick, Maryland, USA
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24
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Ecker M, Joshi-Imre A, Modi R, Frewin CL, Garcia-Sandoval A, Maeng J, Gutierrez-Heredia G, Pancrazio JJ, Voit WE. From softening polymers to multimaterial based bioelectronic devices. ACTA ACUST UNITED AC 2018. [DOI: 10.1088/2399-7532/aaed58] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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25
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Zahn JD. Microdevice Development and Artificial Organs. Artif Organs 2018; 43:17-20. [PMID: 30260017 DOI: 10.1111/aor.13288] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jeffrey D Zahn
- Department of Biomedical Engineering, Rutgers University, 599 Taylor Road, Piscataway, NJ, 08854, USA
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Vallejo-Giraldo C, Krukiewicz K, Calaresu I, Zhu J, Palma M, Fernandez-Yague M, McDowell B, Peixoto N, Farid N, O'Connor G, Ballerini L, Pandit A, Biggs MJP. Attenuated Glial Reactivity on Topographically Functionalized Poly(3,4-Ethylenedioxythiophene):P-Toluene Sulfonate (PEDOT:PTS) Neuroelectrodes Fabricated by Microimprint Lithography. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2018; 14:e1800863. [PMID: 29862640 DOI: 10.1002/smll.201800863] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2018] [Revised: 04/17/2018] [Indexed: 06/08/2023]
Abstract
Following implantation, neuroelectrode functionality is susceptible to deterioration via reactive host cell response and glial scar-induced encapsulation. Within the neuroengineering community, there is a consensus that the induction of selective adhesion and regulated cellular interaction at the tissue-electrode interface can significantly enhance device interfacing and functionality in vivo. In particular, topographical modification holds promise for the development of functionalized neural interfaces to mediate initial cell adhesion and the subsequent evolution of gliosis, minimizing the onset of a proinflammatory glial phenotype, to provide long-term stability. Herein, a low-temperature microimprint-lithography technique for the development of micro-topographically functionalized neuroelectrode interfaces in electrodeposited poly(3,4-ethylenedioxythiophene):p-toluene sulfonate (PEDOT:PTS) is described and assessed in vitro. Platinum (Pt) microelectrodes are subjected to electrodeposition of a PEDOT:PTS microcoating, which is subsequently topographically functionalized with an ordered array of micropits, inducing a significant reduction in electrode electrical impedance and an increase in charge storage capacity. Furthermore, topographically functionalized electrodes reduce the adhesion of reactive astrocytes in vitro, evident from morphological changes in cell area, focal adhesion formation, and the synthesis of proinflammatory cytokines and chemokine factors. This study contributes to the understanding of gliosis in complex primary mixed cell cultures, and describes the role of micro-topographically modified neural interfaces in the development of stable microelectrode interfaces.
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Affiliation(s)
- Catalina Vallejo-Giraldo
- CÚRAM-Centre for Research in Medical Devices-Galway, Biosciences Research Building, 118 Corrib Village, Newcastle, Galway, H91 D577, Ireland
| | - Katarzyna Krukiewicz
- CÚRAM-Centre for Research in Medical Devices-Galway, Biosciences Research Building, 118 Corrib Village, Newcastle, Galway, H91 D577, Ireland
- Department of Physical Chemistry and Technology of Polymers, Silesian University of Technology, Gliwice, 44-100, Poland
| | - Ivo Calaresu
- Scuola Internazionale Superiore di Studi Avanzati (SISSA), Via Bonomea, 265, 34136, Trieste, Italy
| | - Jingyuan Zhu
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London, E14NS, UK
| | - Matteo Palma
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London, E14NS, UK
| | - Marc Fernandez-Yague
- CÚRAM-Centre for Research in Medical Devices-Galway, Biosciences Research Building, 118 Corrib Village, Newcastle, Galway, H91 D577, Ireland
| | - BenjaminW McDowell
- Department of Electrical and Computer Engineering, George Mason University, 4400 University Drive, MS-1G5 Fairfax, VA, 22030, USA
| | - Nathalia Peixoto
- Department of Electrical and Computer Engineering, George Mason University, 4400 University Drive, MS-1G5 Fairfax, VA, 22030, USA
| | - Nazar Farid
- School of Physics, National University of Ireland, Galway, University Road, Galway, H91 CF50, Ireland
| | - Gerard O'Connor
- School of Physics, National University of Ireland, Galway, University Road, Galway, H91 CF50, Ireland
| | - Laura Ballerini
- Scuola Internazionale Superiore di Studi Avanzati (SISSA), Via Bonomea, 265, 34136, Trieste, Italy
| | - Abhay Pandit
- CÚRAM-Centre for Research in Medical Devices-Galway, Biosciences Research Building, 118 Corrib Village, Newcastle, Galway, H91 D577, Ireland
| | - Manus Jonathan Paul Biggs
- CÚRAM-Centre for Research in Medical Devices-Galway, Biosciences Research Building, 118 Corrib Village, Newcastle, Galway, H91 D577, Ireland
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Ngernsutivorakul T, White TS, Kennedy RT. Microfabricated Probes for Studying Brain Chemistry: A Review. Chemphyschem 2018; 19:1128-1142. [PMID: 29405568 PMCID: PMC6996029 DOI: 10.1002/cphc.201701180] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Indexed: 12/13/2022]
Abstract
Probe techniques for monitoring in vivo chemistry (e.g., electrochemical sensors and microdialysis sampling probes) have significantly contributed to a better understanding of neurotransmission in correlation to behaviors and neurological disorders. Microfabrication allows construction of neural probes with high reproducibility, scalability, design flexibility, and multiplexed features. This technology has translated well into fabricating miniaturized neurochemical probes for electrochemical detection and sampling. Microfabricated electrochemical probes provide a better control of spatial resolution with multisite detection on a single compact platform. This development allows the observation of heterogeneity of neurochemical activity precisely within the brain region. Microfabricated sampling probes are starting to emerge that enable chemical measurements at high spatial resolution and potential for reducing tissue damage. Recent advancement in analytical methods also facilitates neurochemical monitoring at high temporal resolution. Furthermore, a positive feature of microfabricated probes is that they can be feasibly built with other sensing and stimulating platforms including optogenetics. Such integrated probes will empower researchers to precisely elucidate brain function and develop novel treatments for neurological disorders.
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Affiliation(s)
| | - Thomas S. White
- Macromolecular Science and Engineering, University of Michigan, 3003E, NCRC Building 28, 2800 Plymouth Rd., Ann Arbor, MI 48109
| | - Robert T. Kennedy
- Department of Chemistry, University of Michigan, 930 N. University Ave, Ann Arbor, MI 48109
- Department of Pharmacology, University of Michigan, 1150 W. Medical Center Drive, Ann Arbor, MI 48109
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Okazawa T, Akita I. A Time-Domain Analog Spatial Compressed Sensing Encoder for Multi-Channel Neural Recording. SENSORS (BASEL, SWITZERLAND) 2018; 18:s18010184. [PMID: 29324675 PMCID: PMC5795473 DOI: 10.3390/s18010184] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Revised: 01/08/2018] [Accepted: 01/08/2018] [Indexed: 06/07/2023]
Abstract
A time-domain analog spatial compressed sensing encoder for neural recording applications is proposed. Owing to the advantage of MEMS technologies, the number of channels on a silicon neural probe array has doubled in 7.4 years, and therefore, a greater number of recording channels and higher density of front-end circuitry is required. Since neural signals such as action potential (AP) have wider signal bandwidth than that of an image sensor, a data compression technique is essentially required for arrayed neural recording systems. In this paper, compressed sensing (CS) is employed for data reduction, and a novel time-domain analog CS encoder is proposed. A simpler and lower power circuit than conventional analog or digital CS encoders can be realized by using the proposed CS encoder. A prototype of the proposed encoder was fabricated in a 180 nm 1P6M CMOS process, and it achieved an active area of 0.0342 mm 2 / ch . and an energy efficiency of 25.0 pJ / ch . · conv .
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Affiliation(s)
- Takayuki Okazawa
- Department of Electrical and Electronic Information Engineering, Toyohashi University of Technology, 1-1 Hibarigaoka, Tempaku-cho, Toyohashi, Aichi 441-8580, Japan.
| | - Ippei Akita
- Department of Electrical and Electronic Information Engineering, Toyohashi University of Technology, 1-1 Hibarigaoka, Tempaku-cho, Toyohashi, Aichi 441-8580, Japan.
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Shahadat M, Khan MZ, Rupani PF, Embrandiri A, Sultana S, Ahammad SZ, Wazed Ali S, Sreekrishnan T. A critical review on the prospect of polyaniline-grafted biodegradable nanocomposite. Adv Colloid Interface Sci 2017; 249:2-16. [PMID: 28935100 DOI: 10.1016/j.cis.2017.08.006] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Revised: 08/18/2017] [Accepted: 08/20/2017] [Indexed: 10/18/2022]
Abstract
Among the various electrically conducting polymers, polyaniline (PANI) has gained attentions due to its unique properties and doping chemistry. A number of electrically conducting biodegradable polymers has been synthesized by incorporating a biodegradable content of cellulose, chitin, chitosan, etc. in the matrix of PANI. The hybrid materials are also employed as photocatalysts, antibacterial agents, sensors, fuel cells and as materials in biomedical applications. Furthermore, these biodegradable and biocompatible conducting polymers are employed in tissue engineering, dental implants and targeted drug delivery. This review presents state of the art of PANI based biodegradable polymers along with their synthesis routes and unique applications in diverse fields. In future, the synthesis of PANI-grafted biodegradable nanocomposite material is expected to open innovative ways for their outstanding applications.
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30
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PDMS based multielectrode arrays for superior in-vitro retinal stimulation and recording. Biomed Microdevices 2017; 19:75. [DOI: 10.1007/s10544-017-0221-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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31
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Sim JY, Haney MP, Park SI, McCall JG, Jeong JW. Microfluidic neural probes: in vivo tools for advancing neuroscience. LAB ON A CHIP 2017; 17:1406-1435. [PMID: 28349140 DOI: 10.1039/c7lc00103g] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Microfluidic neural probes hold immense potential as in vivo tools for dissecting neural circuit function in complex nervous systems. Miniaturization, integration, and automation of drug delivery tools open up new opportunities for minimally invasive implants. These developments provide unprecedented spatiotemporal resolution in fluid delivery as well as multifunctional interrogation of neural activity using combined electrical and optical modalities. Capitalizing on these unique features, microfluidic technology will greatly advance in vivo pharmacology, electrophysiology, optogenetics, and optopharmacology. In this review, we discuss recent advances in microfluidic neural probe systems. In particular, we will highlight the materials and manufacturing processes of microfluidic probes, device configurations, peripheral devices for fluid handling and packaging, and wireless technologies that can be integrated for the control of these microfluidic probe systems. This article summarizes various microfluidic implants and discusses grand challenges and future directions for further developments.
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Affiliation(s)
- Joo Yong Sim
- Electronics and Telecommunications Research Institute, Bio-Medical IT Convergence Research Department, Daejeon, 34129, Republic of Korea
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32
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Novel four-sided neural probe fabricated by a thermal lamination process of polymer films. J Neurosci Methods 2017; 278:25-35. [DOI: 10.1016/j.jneumeth.2016.12.017] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Revised: 12/22/2016] [Accepted: 12/23/2016] [Indexed: 02/02/2023]
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33
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Zhou W, Dai X, Lieber CM. Advances in nanowire bioelectronics. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2017; 80:016701. [PMID: 27823988 DOI: 10.1088/0034-4885/80/1/016701] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Semiconductor nanowires represent powerful building blocks for next generation bioelectronics given their attractive properties, including nanometer-scale footprint comparable to subcellular structures and bio-molecules, configurable in nonstandard device geometries readily interfaced with biological systems, high surface-to-volume ratios, fast signal responses, and minimum consumption of energy. In this review article, we summarize recent progress in the field of nanowire bioelectronics with a focus primarily on silicon nanowire field-effect transistor biosensors. First, the synthesis and assembly of semiconductor nanowires will be described, including the basics of nanowire FETs crucial to their configuration as biosensors. Second, we will introduce and review recent results in nanowire bioelectronics for biomedical applications ranging from label-free sensing of biomolecules, to extracellular and intracellular electrophysiological recording.
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Affiliation(s)
- Wei Zhou
- Bradley Department of Electrical and Computer Engineering, Virginia Tech, Blacksburg, VA 24061, USA
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34
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Flexible, Penetrating Brain Probes Enabled by Advances in Polymer Microfabrication. MICROMACHINES 2016; 7:mi7100180. [PMID: 30404353 PMCID: PMC6190320 DOI: 10.3390/mi7100180] [Citation(s) in RCA: 101] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/23/2016] [Accepted: 09/19/2016] [Indexed: 12/13/2022]
Abstract
The acquisition of high-fidelity, long-term neural recordings in vivo is critically important to advance neuroscience and brain⁻machine interfaces. For decades, rigid materials such as metal microwires and micromachined silicon shanks were used as invasive electrophysiological interfaces to neurons, providing either single or multiple electrode recording sites. Extensive research has revealed that such rigid interfaces suffer from gradual recording quality degradation, in part stemming from tissue damage and the ensuing immune response arising from mechanical mismatch between the probe and brain. The development of "soft" neural probes constructed from polymer shanks has been enabled by advancements in microfabrication; this alternative has the potential to mitigate mismatch-related side effects and thus improve the quality of recordings. This review examines soft neural probe materials and their associated microfabrication techniques, the resulting soft neural probes, and their implementation including custom implantation and electrical packaging strategies. The use of soft materials necessitates careful consideration of surgical placement, often requiring the use of additional surgical shuttles or biodegradable coatings that impart temporary stiffness. Investigation of surgical implantation mechanics and histological evidence to support the use of soft probes will be presented. The review concludes with a critical discussion of the remaining technical challenges and future outlook.
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Neural Probes for Chronic Applications. MICROMACHINES 2016; 7:mi7100179. [PMID: 30404352 PMCID: PMC6190051 DOI: 10.3390/mi7100179] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/09/2016] [Revised: 09/12/2016] [Accepted: 09/26/2016] [Indexed: 12/11/2022]
Abstract
Developed over approximately half a century, neural probe technology is now a mature technology in terms of its fabrication technology and serves as a practical alternative to the traditional microwires for extracellular recording. Through extensive exploration of fabrication methods, structural shapes, materials, and stimulation functionalities, neural probes are now denser, more functional and reliable. Thus, applications of neural probes are not limited to extracellular recording, brain-machine interface, and deep brain stimulation, but also include a wide range of new applications such as brain mapping, restoration of neuronal functions, and investigation of brain disorders. However, the biggest limitation of the current neural probe technology is chronic reliability; neural probes that record with high fidelity in acute settings often fail to function reliably in chronic settings. While chronic viability is imperative for both clinical uses and animal experiments, achieving one is a major technological challenge due to the chronic foreign body response to the implant. Thus, this review aims to outline the factors that potentially affect chronic recording in chronological order of implantation, summarize the methods proposed to minimize each factor, and provide a performance comparison of the neural probes developed for chronic applications.
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36
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Development and application of a microfabricated multimodal neural catheter for neuroscience. Biomed Microdevices 2016; 18:8. [PMID: 26780443 DOI: 10.1007/s10544-016-0034-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
We present a microfabricated neural catheter for real-time continuous monitoring of multiple physiological, biochemical and electrophysiological variables that are critical to the diagnosis and treatment of evolving brain injury. The first generation neural catheter was realized by polyimide-based micromachining and a spiral rolling packaging method. The mechanical design and electrical operation of the microsensors were optimized and tailored for multimodal monitoring in rat brain such that the potential thermal, chemical and electrical crosstalk among the microsensors as well as errors from micro-environmental fluctuations are minimized. In vitro cytotoxicity analyses suggest that the developed neural catheters are minimally toxic to rat cortical neuronal cultures. In addition, in vivo histopathology results showed neither acute nor chronic inflammation for 7 days post implantation. The performance of the neural catheter was assessed in an in vivo needle prick model as a translational replica of a "mini" traumatic brain injury. It successfully monitored the expected transient brain oxygen, temperature, regional cerebral blood flow, and DC potential changes during the passage of spreading depolarization waves. We envisage that the developed multimodal neural catheter can be used to decipher the causes and consequences of secondary brain injury processes with high spatial and temporal resolution while reducing the potential for iatrogenic injury inherent to current use of multiple invasive probes.
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37
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Wu H, Sariola V, Zhao J, Ding H, Sitti M, Bettinger CJ. Composition‐dependent underwater adhesion of catechol‐bearing hydrogels. POLYM INT 2016. [DOI: 10.1002/pi.5246] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Haosheng Wu
- Department of Materials Science and Engineering Carnegie Mellon University Pittsburgh PA 15213 USA
| | - Veikko Sariola
- Department of Mechanical Engineering Carnegie Mellon University Pittsburgh PA 15213 USA
- Department of Electrical Engineering and Automation Aalto University Helsinki 00076 Finland
| | - Jingsi Zhao
- Department of Biomedical Engineering Carnegie Mellon University Pittsburgh PA 15213 USA
| | - Hangjun Ding
- Department of Materials Science and Engineering Carnegie Mellon University Pittsburgh PA 15213 USA
| | - Metin Sitti
- Department of Mechanical Engineering Carnegie Mellon University Pittsburgh PA 15213 USA
- Max Planck Institute for Intelligent Systems Stuttgart 70569 Germany
| | - Christopher J Bettinger
- Department of Materials Science and Engineering Carnegie Mellon University Pittsburgh PA 15213 USA
- Department of Biomedical Engineering Carnegie Mellon University Pittsburgh PA 15213 USA
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38
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Scholvin J, Kinney JP, Bernstein JG, Moore-Kochlacs C, Kopell N, Fonstad CG, Boyden ES. Close-Packed Silicon Microelectrodes for Scalable Spatially Oversampled Neural Recording. IEEE Trans Biomed Eng 2016; 63:120-130. [PMID: 26699649 DOI: 10.1109/tbme.2015.2406113] [Citation(s) in RCA: 116] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
OBJECTIVE Neural recording electrodes are important tools for understanding neural codes and brain dynamics. Neural electrodes that are closely packed, such as in tetrodes, enable spatial oversampling of neural activity, which facilitates data analysis. Here we present the design and implementation of close-packed silicon microelectrodes to enable spatially oversampled recording of neural activity in a scalable fashion. METHODS Our probes are fabricated in a hybrid lithography process, resulting in a dense array of recording sites connected to submicron dimension wiring. RESULTS We demonstrate an implementation of a probe comprising 1000 electrode pads, each 9 × 9 μm, at a pitch of 11 μm. We introduce design automation and packaging methods that allow us to readily create a large variety of different designs. SIGNIFICANCE We perform neural recordings with such probes in the live mammalian brain that illustrate the spatial oversampling potential of closely packed electrode sites.
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Affiliation(s)
- Jorg Scholvin
- MIT Media Lab and McGovern Institute, Massachusetts Institute of Technology, Cambridge, MA
| | - Justin P Kinney
- MIT Media Lab and McGovern Institute, Massachusetts Institute of Technology, Cambridge, MA
| | - Jacob G Bernstein
- MIT Media Lab and McGovern Institute, Massachusetts Institute of Technology, Cambridge, MA
| | | | | | | | - Edward S Boyden
- MIT Media Lab and McGovern Institute, Massachusetts Institute of Technology, Cambridge, MA, USA
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39
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Weltin A, Kieninger J, Urban GA. Microfabricated, amperometric, enzyme-based biosensors for in vivo applications. Anal Bioanal Chem 2016; 408:4503-21. [PMID: 26935934 PMCID: PMC4909808 DOI: 10.1007/s00216-016-9420-4] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2015] [Revised: 02/08/2016] [Accepted: 02/12/2016] [Indexed: 01/19/2023]
Abstract
Miniaturized electrochemical in vivo biosensors allow the measurement of fast extracellular dynamics of neurotransmitter and energy metabolism directly in the tissue. Enzyme-based amperometric biosensing is characterized by high specificity and precision as well as high spatial and temporal resolution. Aside from glucose monitoring, many systems have been introduced mainly for application in the central nervous system in animal models. We compare the microsensor principle with other methods applied in biomedical research to show advantages and drawbacks. Electrochemical sensor systems are easily miniaturized and fabricated by microtechnology processes. We review different microfabrication approaches for in vivo sensor platforms, ranging from simple modified wires and fibres to fully microfabricated systems on silicon, ceramic or polymer substrates. The various immobilization methods for the enzyme such as chemical cross-linking and entrapment in polymer membranes are discussed. The resulting sensor performance is compared in detail. We also examine different concepts to reject interfering substances by additional membranes, aspects of instrumentation and biocompatibility. Practical considerations are elaborated, and conclusions for future developments are presented. Graphical Abstract ᅟ.
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Affiliation(s)
- Andreas Weltin
- Laboratory for Sensors, Department of Microsystems Engineering – IMTEK, University of Freiburg, Georges-Köhler-Allee 103, 79110 Freiburg, Germany
| | - Jochen Kieninger
- Laboratory for Sensors, Department of Microsystems Engineering – IMTEK, University of Freiburg, Georges-Köhler-Allee 103, 79110 Freiburg, Germany
| | - Gerald A. Urban
- Laboratory for Sensors, Department of Microsystems Engineering – IMTEK, University of Freiburg, Georges-Köhler-Allee 103, 79110 Freiburg, Germany
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40
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Computational Assessment of Neural Probe and Brain Tissue Interface under Transient Motion. BIOSENSORS-BASEL 2016; 6:27. [PMID: 27322338 PMCID: PMC4931487 DOI: 10.3390/bios6020027] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/06/2016] [Revised: 06/02/2016] [Accepted: 06/06/2016] [Indexed: 01/25/2023]
Abstract
The functional longevity of a neural probe is dependent upon its ability to minimize injury risk during the insertion and recording period in vivo, which could be related to motion-related strain between the probe and surrounding tissue. A series of finite element analyses was conducted to study the extent of the strain induced within the brain in an area around a neural probe. This study focuses on the transient behavior of neural probe and brain tissue interface with a viscoelastic model. Different stages of the interface from initial insertion of neural probe to full bonding of the probe by astro-glial sheath formation are simulated utilizing analytical tools to investigate the effects of relative motion between the neural probe and the brain while friction coefficients and kinematic frequencies are varied. The analyses can provide an in-depth look at the quantitative benefits behind using soft materials for neural probes.
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41
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Lee JH, Kim H, Kim JH, Lee SH. Soft implantable microelectrodes for future medicine: prosthetics, neural signal recording and neuromodulation. LAB ON A CHIP 2016; 16:959-76. [PMID: 26891410 DOI: 10.1039/c5lc00842e] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Implantable devices have provided various potential diagnostic options and therapeutic methods in diverse medical fields. A variety of hard-material-based implantable electrodes have been developed. However, several limitations for their chronic implantation remain, including mechanical mismatches at the interface between the electrode and the soft tissue, and biocompatibility. Soft-material-based implantable devices are suitable candidates for complementing the limitations of hard electrodes. Advances in microtechnology and materials science have largely solved many challenges, such as optimization of shape, minimization of infection, enhancement of biocompatibility and integration with components for diverse functions. Significant strides have also been made in mechanical matching of electrodes to soft tissue. In this review, we provide an overview of recent advances in soft-material-based implantable electrodes for medical applications, categorized according to their implantation site and material composition. We then review specific applications in three categories: neuroprosthetics, neural signal recording, and neuromodulation. Finally, we describe various strategies for the future development and application of implantable, soft-material-based devices.
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Affiliation(s)
- Joong Hoon Lee
- KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul 136-701, Republic of Korea
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42
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Abstract
Nano-bioelectronics represents a rapidly expanding interdisciplinary field that combines nanomaterials with biology and electronics and, in so doing, offers the potential to overcome existing challenges in bioelectronics. In particular, shrinking electronic transducer dimensions to the nanoscale and making their properties appear more biological can yield significant improvements in the sensitivity and biocompatibility and thereby open up opportunities in fundamental biology and healthcare. This review emphasizes recent advances in nano-bioelectronics enabled with semiconductor nanostructures, including silicon nanowires, carbon nanotubes, and graphene. First, the synthesis and electrical properties of these nanomaterials are discussed in the context of bioelectronics. Second, affinity-based nano-bioelectronic sensors for highly sensitive analysis of biomolecules are reviewed. In these studies, semiconductor nanostructures as transistor-based biosensors are discussed from fundamental device behavior through sensing applications and future challenges. Third, the complex interface between nanoelectronics and living biological systems, from single cells to live animals, is reviewed. This discussion focuses on representative advances in electrophysiology enabled using semiconductor nanostructures and their nanoelectronic devices for cellular measurements through emerging work where arrays of nanoelectronic devices are incorporated within three-dimensional cell networks that define synthetic and natural tissues. Last, some challenges and exciting future opportunities are discussed.
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Affiliation(s)
- Anqi Zhang
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts, 02138, United States
| | - Charles M. Lieber
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts, 02138, United States
- Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts, 02138, United States
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43
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Xie C, Liu J, Fu TM, Dai X, Zhou W, Lieber CM. Three-dimensional macroporous nanoelectronic networks as minimally invasive brain probes. NATURE MATERIALS 2015; 14:1286-1292. [PMID: 26436341 DOI: 10.1038/nmat4427] [Citation(s) in RCA: 236] [Impact Index Per Article: 23.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2015] [Accepted: 08/19/2015] [Indexed: 06/05/2023]
Abstract
Direct electrical recording and stimulation of neural activity using micro-fabricated silicon and metal micro-wire probes have contributed extensively to basic neuroscience and therapeutic applications; however, the dimensional and mechanical mismatch of these probes with the brain tissue limits their stability in chronic implants and decreases the neuron-device contact. Here, we demonstrate the realization of a three-dimensional macroporous nanoelectronic brain probe that combines ultra-flexibility and subcellular feature sizes to overcome these limitations. Built-in strains controlling the local geometry of the macroporous devices are designed to optimize the neuron/probe interface and to promote integration with the brain tissue while introducing minimal mechanical perturbation. The ultra-flexible probes were implanted frozen into rodent brains and used to record multiplexed local field potentials and single-unit action potentials from the somatosensory cortex. Significantly, histology analysis revealed filling-in of neural tissue through the macroporous network and attractive neuron-probe interactions, consistent with long-term biocompatibility of the device.
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Affiliation(s)
- Chong Xie
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Jia Liu
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Tian-Ming Fu
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Xiaochuan Dai
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Wei Zhou
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Charles M Lieber
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, USA
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA
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44
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Silicon/SU8 multi-electrode micro-needle for in vivo neurochemical monitoring. Biosens Bioelectron 2015; 72:148-55. [DOI: 10.1016/j.bios.2015.05.004] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2015] [Accepted: 05/05/2015] [Indexed: 11/23/2022]
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Ceyssens F, Puers R. Insulation lifetime improvement of polyimide thin film neural implants. J Neural Eng 2015; 12:054001. [DOI: 10.1088/1741-2560/12/5/054001] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Alvarez-Mejia L, Morales J, Cruz GJ, Olayo MG, Olayo R, Díaz-Ruíz A, Ríos C, Mondragón-Lozano R, Sánchez-Torres S, Morales-Guadarrama A, Fabela-Sánchez O, Salgado-Ceballos H. Functional recovery in spinal cord injured rats using polypyrrole/iodine implants and treadmill training. JOURNAL OF MATERIALS SCIENCE. MATERIALS IN MEDICINE 2015; 26:209. [PMID: 26169188 DOI: 10.1007/s10856-015-5541-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2015] [Accepted: 07/03/2015] [Indexed: 06/04/2023]
Abstract
Currently, there is no universally accepted treatment for traumatic spinal cord injury (TSCI), a pathology that can cause paraplegia or quadriplegia. Due to the complexity of TSCI, more than one therapeutic strategy may be necessary to regain lost functions. Therefore, the present study proposes the use of implants of mesoparticles (MPs) of polypyrrole/iodine (PPy/I) synthesized by plasma for neuroprotection promotion and functional recovery in combination with treadmill training (TT) for neuroplasticity promotion and maintenance of muscle tone. PPy/I films were synthesized by plasma and pulverized to obtain MPs. Rats with a TSCI produced by the NYU impactor were divided into four groups: Vehicle (saline solution); MPs (PPy/I implant); Vehicle-TT (saline solution + TT); and MPs-TT (PPy/I implant + TT). The vehicle or MPs (30 μL) were injected into the lesion site 48 h after a TSCI. Four days later, TT was carried out 5 days a week for 2 months. Functional recovery was evaluated weekly using the BBB motor scale for 9 weeks and tissue protection using histological and morphometric analysis thereafter. Although the MPs of PPy/I increased nerve tissue preservation (P = 0.03) and promoted functional recovery (P = 0.015), combination with TT did not produce better neuroprotection, but significantly improved functional results (P = 0.000) when comparing with the vehicle group. So, use these therapeutic strategies by separately could stimulate specific mechanisms of neuroprotection and neuroregeneration, but when using together they could mainly potentiate different mechanisms of neuronal plasticity in the preserved spinal cord tissue after a TSCI and produce a significant functional recovery. The implant of mesoparticles of polypyrrole/iodine into the injured spinal cord displayed good integration into the nervous tissue without a response of rejection, as well as an increased in the amount of preserved tissue and a better functional recovery than the group without transplant after a traumatic spinal cord injury by contusion in rats. The relevance of the present results is that polypyrrole/iodine implants were synthesized by plasma instead by conventional chemical or electrochemical methods. Synthesis by plasma modifies physicochemical properties of polypyrrole/iodine implants, which can be responsible of the histological response and functional results. Furthermore, no additional molecules or trophic factors or cells were added to the implant for obtain such results. Even more, when the implant was used together with physical rehabilitation, better functional recovery was obtained than that observed when these strategies were used by separately.
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Affiliation(s)
- Laura Alvarez-Mejia
- Department of Electric Engineering, Universidad Autónoma Metropolitana Iztapalapa, Apdo. Postal 55-534, CP 09340, Mexico, DF, Mexico
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Jeong JW, Shin G, Park SI, Yu KJ, Xu L, Rogers JA. Soft materials in neuroengineering for hard problems in neuroscience. Neuron 2015; 86:175-86. [PMID: 25856493 DOI: 10.1016/j.neuron.2014.12.035] [Citation(s) in RCA: 184] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
We describe recent advances in soft electronic interface technologies for neuroscience research. Here, low modulus materials and/or compliant mechanical structures enable modes of soft, conformal integration and minimally invasive operation that would be difficult or impossible to achieve using conventional approaches. We begin by summarizing progress in electrodes and associated electronics for signal amplification and multiplexed readout. Examples in large-area, surface conformal electrode arrays and flexible, multifunctional depth-penetrating probes illustrate the power of these concepts. A concluding section highlights areas of opportunity in the further development and application of these technologies.
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Affiliation(s)
- Jae-Woong Jeong
- Department of Materials Science and Engineering, Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Gunchul Shin
- Department of Materials Science and Engineering, Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Sung Il Park
- Department of Materials Science and Engineering, Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Ki Jun Yu
- Department of Electrical and Computer Engineering, Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Lizhi Xu
- Department of Materials Science and Engineering, Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - John A Rogers
- Department of Materials Science and Engineering, Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA; Department of Electrical and Computer Engineering, Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
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Yi W, Chen C, Feng Z, Xu Y, Zhou C, Masurkar N, Cavanaugh J, Cheng MMC. A flexible and implantable microelectrode arrays using high-temperature grown vertical carbon nanotubes and a biocompatible polymer substrate. NANOTECHNOLOGY 2015; 26:125301. [PMID: 25742874 DOI: 10.1088/0957-4484/26/12/125301] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
This paper presents a novel microelectrode arrays using high-temperature grown vertically aligned carbon nanotubes (CNTs) integrated on a flexible and biocompatible parylene substrate. A simple microfabrication process is proposed to unite the high quality vertical CNTs grown at high temperature with the heat sensitive parylene substrate in a highly controllable manner. Briefly, the CNTs electrode is encapsulated by two layers of parylene and the device is released using xenon difluoride (XeF2). The process is compatible with wafer-scale post complementary metal oxide semiconductor integration. Lower impedance and larger interfacial capacitance have been demonstrated using CNTs compared to a Pt electrode. The flexible CNT electrodes have been utilized for extracellular neuronal recording and stimulation in rats. The signal-to-noise ratio of the device is about 12.5. The threshold voltage for initiating action potential is about 0.5 V.
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Affiliation(s)
- Wenwen Yi
- Electrical and Computer Engineering, Detroit MI USA
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Fekete Z, Németh A, Márton G, Ulbert I, Pongrácz A. Experimental study on the mechanical interaction between silicon neural microprobes and rat dura mater during insertion. JOURNAL OF MATERIALS SCIENCE. MATERIALS IN MEDICINE 2015; 26:70. [PMID: 25631267 DOI: 10.1007/s10856-015-5401-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2014] [Accepted: 10/26/2014] [Indexed: 05/06/2023]
Abstract
In vivo insertion experiments are essential to optimize novel neural implants. Our work focuses on the interaction between intact dura mater of rats and as-fabricated single-shaft silicon microprobes realized by deep reactive ion etching. Implantation parameters like penetration force and dimpling through intact dura mater were studied as a function of insertion speed, microprobe cross-section, tip angle and animal age. To reduce tissue resistance, we proposed a unique tip sharpening technique, which was also evaluated in in vivo insertion tests. By doubling the insertion speed (between 1.2 and 10.5 mm/min), an increase of 10-35% in penetration forces was measured. When decreasing the cross-section of the microprobes, penetration forces and dimpling was reduced by as much as 30-50% at constant insertion speeds. Force was noticed to gradually decrease by decreasing tip angles. Measured penetration forces through dura mater were reduced even down to 11±3 mN compared to unsharpened (49±13 mN) probes by utilizing our unique tip sharpening technique, which is very close to exerted penetration force in the case of retracted dura (5±1.5 mN). Our findings imply that age remarkably alters the elasticity of intact dura mater. The decreasing stiffness of dura mater results in a significant rise in penetration force and decrease in dimpling. Our work is the first in vivo comparative study on microelectrode penetration through intact and retracted dura mater.
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Affiliation(s)
- Z Fekete
- MEMS Lab, Institute for Technical Physics & Material Science, RCNS, HAS, P.O.Box 49, Budapest, 1525, Hungary,
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