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Murphy BB, Apollo NV, Unegbu P, Posey T, Rodriguez-Perez N, Hendricks Q, Cimino F, Richardson AG, Vitale F. Vitamin C-reduced graphene oxide improves the performance and stability of multimodal neural microelectrodes. iScience 2022; 25:104652. [PMID: 35811842 PMCID: PMC9263525 DOI: 10.1016/j.isci.2022.104652] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Revised: 05/28/2022] [Accepted: 06/16/2022] [Indexed: 11/28/2022] Open
Abstract
Nanocarbons are often employed as coatings for neural electrodes to enhance surface area. However, processing and integrating them into microfabrication flows requires complex and harmful chemical and heating conditions. This article presents a safe, scalable, cost-effective method to produce reduced graphene oxide (rGO) coatings using vitamin C (VC) as the reducing agent. We spray coat GO + VC mixtures onto target substrates, and then heat samples for 15 min at 150°C. The resulting rGO films have conductivities of ∼44 S cm−1, and are easily integrated into an ad hoc microfabrication flow. The rGO/Au microelectrodes show ∼8x lower impedance and ∼400x higher capacitance than bare Au, resulting in significantly enhanced charge storage and injection capacity. We subsequently use rGO/Au arrays to detect dopamine in vitro, and to map cortical activity intraoperatively over rat whisker barrel cortex, demonstrating that conductive VC-rGO coatings improve the performance and stability of multimodal microelectrodes for different applications. Easy, scalable, and safe reduction method to create rGO films with vitamin C VC-rGO coatings improve the performance of bare gold microelectrodes in vitro VC-rGO coatings enable the voltammetric detection of dopamine on the microscale rGO/Au electrode arrays enable high-resolution microscale recording in vivo
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Affiliation(s)
- Brendan B. Murphy
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104, USA
- Center for Neuroengineering and Therapeutics, University of Pennsylvania, Philadelphia, PA 19104, USA
- Center for Neurotrauma, Neurodegeneration and Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, PA 19104, USA
| | - Nicholas V. Apollo
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104, USA
- Center for Neuroengineering and Therapeutics, University of Pennsylvania, Philadelphia, PA 19104, USA
- Center for Neurotrauma, Neurodegeneration and Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, PA 19104, USA
| | - Placid Unegbu
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104, USA
- Center for Neuroengineering and Therapeutics, University of Pennsylvania, Philadelphia, PA 19104, USA
- Center for Neurotrauma, Neurodegeneration and Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, PA 19104, USA
| | - Tessa Posey
- Department of Biomedical Engineering, University of South Carolina, Columbia, SC 29206, USA
| | - Nancy Rodriguez-Perez
- School of Sustainable Engineering and the Built Environment, Arizona State University, Tempe, AZ 85281, USA
| | - Quincy Hendricks
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104, USA
- Center for Neuroengineering and Therapeutics, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Francesca Cimino
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104, USA
- Center for Neuroengineering and Therapeutics, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Andrew G. Richardson
- Center for Neuroengineering and Therapeutics, University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Neurosurgery, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Flavia Vitale
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104, USA
- Center for Neuroengineering and Therapeutics, University of Pennsylvania, Philadelphia, PA 19104, USA
- Center for Neurotrauma, Neurodegeneration and Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, PA 19104, USA
- Department of Physical Medicine and Rehabilitation, University of Pennsylvania, Philadelphia, PA 19146, USA
- Corresponding author
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Zare I, Yaraki MT, Speranza G, Najafabadi AH, Haghighi AS, Nik AB, Manshian BB, Saraiva C, Soenen SJ, Kogan MJ, Lee JW, Apollo NV, Bernardino L, Araya E, Mayer D, Mao G, Hamblin MR. Gold nanostructures: synthesis, properties, and neurological applications. Chem Soc Rev 2022; 51:2601-2680. [PMID: 35234776 DOI: 10.1039/d1cs01111a] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Recent advances in technology are expected to increase our current understanding of neuroscience. Nanotechnology and nanomaterials can alter and control neural functionality in both in vitro and in vivo experimental setups. The intersection between neuroscience and nanoscience may generate long-term neural interfaces adapted at the molecular level. Owing to their intrinsic physicochemical characteristics, gold nanostructures (GNSs) have received much attention in neuroscience, especially for combined diagnostic and therapeutic (theragnostic) purposes. GNSs have been successfully employed to stimulate and monitor neurophysiological signals. Hence, GNSs could provide a promising solution for the regeneration and recovery of neural tissue, novel neuroprotective strategies, and integrated implantable materials. This review covers the broad range of neurological applications of GNS-based materials to improve clinical diagnosis and therapy. Sub-topics include neurotoxicity, targeted delivery of therapeutics to the central nervous system (CNS), neurochemical sensing, neuromodulation, neuroimaging, neurotherapy, tissue engineering, and neural regeneration. It focuses on core concepts of GNSs in neurology, to circumvent the limitations and significant obstacles of innovative approaches in neurobiology and neurochemistry, including theragnostics. We will discuss recent advances in the use of GNSs to overcome current bottlenecks and tackle technical and conceptual challenges.
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Affiliation(s)
- Iman Zare
- Research and Development Department, Sina Medical Biochemistry Technologies Co. Ltd., Shiraz 7178795844, Iran
| | | | - Giorgio Speranza
- CMM - FBK, v. Sommarive 18, 38123 Trento, Italy.,IFN - CNR, CSMFO Lab., via alla Cascata 56/C Povo, 38123 Trento, Italy.,Department of Industrial Engineering, University of Trento, v. Sommarive 9, 38123 Trento, Italy
| | - Alireza Hassani Najafabadi
- Terasaki Institute for Biomedical Innovation (TIBI), Los Angeles, CA 90064, USA.,Department of Pharmaceutical Sciences, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Alireza Shourangiz Haghighi
- Department of Mechanical Engineering, Shiraz University of Technology, Modarres Boulevard, 13876-71557, Shiraz, Iran
| | - Amirala Bakhshian Nik
- Department of Biomedical Engineering, Florida International University, Miami, FL 33174, USA
| | - Bella B Manshian
- Translational Cell and Tissue Research Unit, Department of Imaging and Pathology, KU Leuven, Herestraat 49, B3000 Leuven, Belgium
| | - Cláudia Saraiva
- Luxembourg Centre for Systems Biomedicine (LCSB), University of Luxembourg, 7 Avenue des Hauts-Fourneaux, 4362 Esch-sur-Alzette, Luxembourg.,Health Sciences Research Centre (CICS-UBI), University of Beira Interior, Rua Marques d'Avila e Bolama, 6201-001 Covilha, Portugal
| | - Stefaan J Soenen
- NanoHealth and Optical Imaging Group, Department of Imaging and Pathology, KU Leuven, Herestraat 49, B3000 Leuven, Belgium
| | - Marcelo J Kogan
- Advanced Center for Chronic Diseases (ACCDiS), Facultad de Ciencias Químicas y Farmacéuticas, Departamento de Química Farmacológica y Toxicológica, Universidad de Chile, 8380492 Santiago, Chile
| | - Jee Woong Lee
- Department of Medical Sciences, Clinical Neurophysiology, Uppsala University, Uppsala, SE-751 23, Sweden
| | - Nicholas V Apollo
- Center for Neuroengineering and Therapeutics, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.,School of Physics, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Liliana Bernardino
- Health Sciences Research Centre (CICS-UBI), University of Beira Interior, Rua Marques d'Avila e Bolama, 6201-001 Covilha, Portugal
| | - Eyleen Araya
- Departamento de Ciencias Quimicas, Facultad de Ciencias Exactas, Universidad Andres Bello, Av. Republica 275, Santiago, Chile
| | - Dirk Mayer
- Institute of Biological Information Processing, Bioelectronics (IBI-3), Forschungszentrum Jülich GmbH, Germany
| | - Guangzhao Mao
- School of Chemical Engineering, University of New South Wales (UNSW Sydney), Sydney, NSW 2052, Australia
| | - Michael R Hamblin
- Laser Research Center, University of Johannesburg, Doorfontein 2028, South Africa.
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3
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Driscoll N, Erickson B, Murphy BB, Richardson AG, Robbins G, Apollo NV, Mentzelopoulos G, Mathis T, Hantanasirisakul K, Bagga P, Gullbrand SE, Sergison M, Reddy R, Wolf JA, Chen HI, Lucas TH, Dillingham T, Davis KA, Gogotsi Y, Medaglia JD, Vitale F. MXene-infused bioelectronic interfaces for multiscale electrophysiology and stimulation. Sci Transl Med 2021; 13:eabf8629. [PMID: 34550728 PMCID: PMC8722432 DOI: 10.1126/scitranslmed.abf8629] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Soft bioelectronic interfaces for mapping and modulating excitable networks at high resolution and at large scale can enable paradigm-shifting diagnostics, monitoring, and treatment strategies. Yet, current technologies largely rely on materials and fabrication schemes that are expensive, do not scale, and critically limit the maximum attainable resolution and coverage. Solution processing is a cost-effective manufacturing alternative, but biocompatible conductive inks matching the performance of conventional metals are lacking. Here, we introduce MXtrodes, a class of soft, high-resolution, large-scale bioelectronic interfaces enabled by Ti3C2 MXene (a two-dimensional transition metal carbide nanomaterial) and scalable solution processing. We show that the electrochemical properties of MXtrodes exceed those of conventional materials and do not require conductive gels when used in epidermal electronics. Furthermore, we validate MXtrodes in applications ranging from mapping large-scale neuromuscular networks in humans to cortical neural recording and microstimulation in swine and rodent models. Last, we demonstrate that MXtrodes are compatible with standard clinical neuroimaging modalities.
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Affiliation(s)
- Nicolette Driscoll
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104, USA
- Center for Neuroengineering and Therapeutics, University of Pennsylvania, Philadelphia, PA 19104, USA
- Center for Neurotrauma, Neurodegeneration, and Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, PA 19104, USA
| | - Brian Erickson
- Department of Psychology, Drexel University, Philadelphia, PA 19104, USA
| | - Brendan B. Murphy
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104, USA
- Center for Neuroengineering and Therapeutics, University of Pennsylvania, Philadelphia, PA 19104, USA
- Center for Neurotrauma, Neurodegeneration, and Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, PA 19104, USA
| | - Andrew G. Richardson
- Center for Neuroengineering and Therapeutics, University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Neurosurgery, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Gregory Robbins
- Department of Physical Medicine and Rehabilitation, University of Pennsylvania, PA 19104, USA
| | - Nicholas V. Apollo
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104, USA
- Center for Neuroengineering and Therapeutics, University of Pennsylvania, Philadelphia, PA 19104, USA
- Center for Neurotrauma, Neurodegeneration, and Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, PA 19104, USA
| | - Georgios Mentzelopoulos
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104, USA
- Center for Neuroengineering and Therapeutics, University of Pennsylvania, Philadelphia, PA 19104, USA
- Center for Neurotrauma, Neurodegeneration, and Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, PA 19104, USA
| | - Tyler Mathis
- Department of Materials Science and Engineering, Drexel University, Philadelphia, PA 19104, USA
- A.J. Drexel Nanomaterials Institute, Drexel University, Philadelphia, PA 19104, USA
| | - Kanit Hantanasirisakul
- Department of Materials Science and Engineering, Drexel University, Philadelphia, PA 19104, USA
- A.J. Drexel Nanomaterials Institute, Drexel University, Philadelphia, PA 19104, USA
| | - Puneet Bagga
- Department of Radiology, Center for Magnetic Resonance and Optical Imaging, University of Pennsylvania, Philadelphia, PA 19104, USA
- Diagnostic Imaging, St Jude Children’s Research Hospital, Memphis, TN 38105, USA
| | - Sarah E. Gullbrand
- Translational Musculoskeletal Research Center, Corporal Michael J. Crescenz VA Medical Center, Philadelphia, PA 19104, USA
- McKay Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Matthew Sergison
- Center for Neurotrauma, Neurodegeneration, and Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, PA 19104, USA
- Department of Neurosurgery, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Ravinder Reddy
- Department of Radiology, Center for Magnetic Resonance and Optical Imaging, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - John A. Wolf
- Center for Neurotrauma, Neurodegeneration, and Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, PA 19104, USA
- Department of Neurosurgery, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - H. Isaac Chen
- Center for Neurotrauma, Neurodegeneration, and Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, PA 19104, USA
- Department of Neurosurgery, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Timothy H. Lucas
- Center for Neuroengineering and Therapeutics, University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Neurosurgery, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Timothy Dillingham
- Department of Physical Medicine and Rehabilitation, University of Pennsylvania, PA 19104, USA
| | - Kathryn A. Davis
- Center for Neuroengineering and Therapeutics, University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Neurology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Yury Gogotsi
- Department of Materials Science and Engineering, Drexel University, Philadelphia, PA 19104, USA
- A.J. Drexel Nanomaterials Institute, Drexel University, Philadelphia, PA 19104, USA
| | - John D. Medaglia
- Department of Psychology, Drexel University, Philadelphia, PA 19104, USA
- Department of Neurology, University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Neurology, Drexel University, Philadelphia, PA 19104, USA
| | - Flavia Vitale
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104, USA
- Center for Neuroengineering and Therapeutics, University of Pennsylvania, Philadelphia, PA 19104, USA
- Center for Neurotrauma, Neurodegeneration, and Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, PA 19104, USA
- Department of Physical Medicine and Rehabilitation, University of Pennsylvania, PA 19104, USA
- Department of Neurology, University of Pennsylvania, Philadelphia, PA 19104, USA
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Murphy BB, Scheid BH, Hendricks Q, Apollo NV, Litt B, Vitale F. Time Evolution of the Skin-Electrode Interface Impedance under Different Skin Treatments. Sensors (Basel) 2021; 21:5210. [PMID: 34372446 PMCID: PMC8348734 DOI: 10.3390/s21155210] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/04/2021] [Revised: 07/22/2021] [Accepted: 07/29/2021] [Indexed: 01/04/2023]
Abstract
A low and stable impedance at the skin-electrode interface is key to high-fidelity acquisition of biosignals, both acutely and in the long term. However, recording quality is highly variable due to the complex nature of human skin. Here, we present an experimental and modeling framework to investigate the interfacial impedance behavior, and describe how skin interventions affect its stability over time. To illustrate this approach, we report experimental measurements on the skin-electrode impedance using pre-gelled, clinical-grade electrodes in healthy human subjects recorded over 24 h following four skin treatments: (i) mechanical abrasion, (ii) chemical exfoliation, (iii) microporation, and (iv) no treatment. In the immediate post-treatment period, mechanical abrasion yields the lowest initial impedance, whereas the other treatments provide modest improvement compared to untreated skin. After 24 h, however, the impedance becomes more uniform across all groups (<20 kΩ at 10 Hz). The impedance data are fitted with an equivalent circuit model of the complete skin-electrode interface, clearly identifying skin-level versus electrode-level contributions to the overall impedance. Using this model, we systematically investigate how time and treatment affect the impedance response, and show that removal of the superficial epidermal layers is essential to achieving a low, long-term stable interface impedance.
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Affiliation(s)
- Brendan B. Murphy
- Department of Bioengineering, 240 Skirkanich Hall, University of Pennsylvania, 210 S. 33rd Street, Philadelphia, PA 19104, USA; (B.B.M.); (B.H.S.); (Q.H.); (B.L.)
- Center for Neuroengineering & Therapeutics, 301 Hayden Hall, University of Pennsylvania, 240 S. 33rd Street, Philadelphia, PA 19104, USA;
- Center for Neurotrauma, Neurodegeneration, and Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, 3900 Woodlawn Ave., Philadelphia, PA 19104, USA
| | - Brittany H. Scheid
- Department of Bioengineering, 240 Skirkanich Hall, University of Pennsylvania, 210 S. 33rd Street, Philadelphia, PA 19104, USA; (B.B.M.); (B.H.S.); (Q.H.); (B.L.)
- Center for Neuroengineering & Therapeutics, 301 Hayden Hall, University of Pennsylvania, 240 S. 33rd Street, Philadelphia, PA 19104, USA;
| | - Quincy Hendricks
- Department of Bioengineering, 240 Skirkanich Hall, University of Pennsylvania, 210 S. 33rd Street, Philadelphia, PA 19104, USA; (B.B.M.); (B.H.S.); (Q.H.); (B.L.)
- Center for Neuroengineering & Therapeutics, 301 Hayden Hall, University of Pennsylvania, 240 S. 33rd Street, Philadelphia, PA 19104, USA;
- Center for Neurotrauma, Neurodegeneration, and Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, 3900 Woodlawn Ave., Philadelphia, PA 19104, USA
| | - Nicholas V. Apollo
- Center for Neuroengineering & Therapeutics, 301 Hayden Hall, University of Pennsylvania, 240 S. 33rd Street, Philadelphia, PA 19104, USA;
- Center for Neurotrauma, Neurodegeneration, and Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, 3900 Woodlawn Ave., Philadelphia, PA 19104, USA
| | - Brian Litt
- Department of Bioengineering, 240 Skirkanich Hall, University of Pennsylvania, 210 S. 33rd Street, Philadelphia, PA 19104, USA; (B.B.M.); (B.H.S.); (Q.H.); (B.L.)
- Center for Neuroengineering & Therapeutics, 301 Hayden Hall, University of Pennsylvania, 240 S. 33rd Street, Philadelphia, PA 19104, USA;
- Department of Neurology, University of Pennsylvania, 3400 Spruce Street, Philadelphia, PA 19104, USA
| | - Flavia Vitale
- Department of Bioengineering, 240 Skirkanich Hall, University of Pennsylvania, 210 S. 33rd Street, Philadelphia, PA 19104, USA; (B.B.M.); (B.H.S.); (Q.H.); (B.L.)
- Center for Neuroengineering & Therapeutics, 301 Hayden Hall, University of Pennsylvania, 240 S. 33rd Street, Philadelphia, PA 19104, USA;
- Center for Neurotrauma, Neurodegeneration, and Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, 3900 Woodlawn Ave., Philadelphia, PA 19104, USA
- Department of Neurology, University of Pennsylvania, 3400 Spruce Street, Philadelphia, PA 19104, USA
- Department of Physical Medicine & Rehabilitation, University of Pennsylvania, 1800 Lombard Street, Philadelphia, PA 19147, USA
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5
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Apollo NV, Murphy B, Prezelski K, Driscoll N, Richardson AG, Lucas TH, Vitale F. Gels, jets, mosquitoes, and magnets: a review of implantation strategies for soft neural probes. J Neural Eng 2020; 17:041002. [PMID: 32759476 PMCID: PMC8152109 DOI: 10.1088/1741-2552/abacd7] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Implantable neuroelectronic interfaces have enabled breakthrough advances in the clinical diagnosis and treatment of neurological disorders, as well as in fundamental studies of brain function, behavior, and disease. Intracranial electroencephalography (EEG) mapping with stereo-EEG (sEEG) depth electrodes is routinely adopted for precise epilepsy diagnostics and surgical treatment, while deep brain stimulation has become the standard of care for managing movement disorders. Intracortical microelectrode arrays for high-fidelity recordings of neural spiking activity have led to impressive demonstrations of the power of brain-machine interfaces for motor and sensory functional recovery. Yet, despite the rapid pace of technology development, the issue of establishing a safe, long-term, stable, and functional interface between neuroelectronic devices and the host brain tissue still remains largely unresolved. A body of work spanning at least the last 15 years suggests that safe, chronic integration between invasive electrodes and the brain requires a close match between the mechanical properties of man-made components and the neural tissue. In other words, the next generation of invasive electrodes should be soft and compliant, without sacrificing biological and chemical stability. Soft neuroelectronic interfaces, however, pose a new and significant surgical challenge: bending and buckling during implantation that can preclude accurate and safe device placement. In this topical review, we describe the next generation of soft electrodes and the surgical implantation methods for safe and precise insertion into brain structures. We provide an overview of the most recent innovations in the field of insertion strategies for flexible neural electrodes such as dissolvable or biodegradable carriers, microactuators, biologically-inspired support structures, and electromagnetic drives. In our analysis, we also highlight approaches developed in different fields, such as robotic surgery, which could be potentially adapted and translated to the insertion of flexible neural probes.
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Affiliation(s)
- Nicholas V Apollo
- Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States of America
- Center for Neuroengineering and Therapeutics, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States of America
- Center for Neurotrauma, Neurodegeneration, and Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, Pennsylvania, 19104, United States of America
| | - Brendan Murphy
- Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States of America
- Center for Neuroengineering and Therapeutics, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States of America
- Center for Neurotrauma, Neurodegeneration, and Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, Pennsylvania, 19104, United States of America
- These authors contributed equally
| | - Kayla Prezelski
- Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States of America
- Center for Neuroengineering and Therapeutics, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States of America
- Center for Neurotrauma, Neurodegeneration, and Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, Pennsylvania, 19104, United States of America
- These authors contributed equally
| | - Nicolette Driscoll
- Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States of America
- Center for Neuroengineering and Therapeutics, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States of America
- Center for Neurotrauma, Neurodegeneration, and Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, Pennsylvania, 19104, United States of America
| | - Andrew G Richardson
- Center for Neuroengineering and Therapeutics, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States of America
- Department of Neurosurgery, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States of America
| | - Timothy H Lucas
- Center for Neuroengineering and Therapeutics, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States of America
- Department of Neurosurgery, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States of America
| | - Flavia Vitale
- Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States of America
- Center for Neuroengineering and Therapeutics, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States of America
- Center for Neurotrauma, Neurodegeneration, and Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, Pennsylvania, 19104, United States of America
- These authors contributed equally
- Department of Neurology, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States of America
- Department of Physical Medicine & Rehabilitation, University of Pennsylvania, Philadelphia, Pennsylvania, 19104, United States of America
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Murphy BB, Mulcahey PJ, Driscoll N, Richardson AG, Robbins GT, Apollo NV, Maleski K, Lucas TH, Gogotsi Y, Dillingham T, Vitale F. A gel-free Ti 3C 2T x-based electrode array for high-density, high-resolution surface electromyography. Adv Mater Technol 2020; 5:2000325. [PMID: 33693054 PMCID: PMC7939071 DOI: 10.1002/admt.202000325] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Indexed: 05/20/2023]
Abstract
Wearable sensors for surface electromyography (EMG) are composed of single- to few-channel large-area contacts, which exhibit high interfacial impedance and require conductive gels or adhesives to record high-fidelity signals. These devices are also limited in their ability to record activation across large muscle groups due to poor spatial coverage. To address these challenges, we have developed a novel high-density EMG array based on titanium carbide (Ti3C2Tx) MXene encapsulated in parylene-C. Ti3C2Tx is a two-dimensional nanomaterial with excellent electrical, electrochemical, and mechanical properties, which forms colloidally stable aqueous dispersions, enabling safe, scalable solutions-processing. Leveraging the excellent combination of metallic conductivity, high pseudocapacitance, and ease of processability of Ti3C2Tx MXene, we demonstrate the fabrication of gel-free, high-density EMG arrays which are ~8 μm thick, feature 16 recording channels, and are highly skin-conformable. The impedance of Ti3C2Tx electrodes in contact with human skin is 100-1000x lower than the impedance of commercially-available electrodes which require conductive gels to be effective. Furthermore, our arrays can record high-fidelity, low-noise EMG, and can resolve muscle activation with improved spatiotemporal resolution and sensitivity compared to conventional gelled electrodes. Overall, our results establish Ti3C2Tx-based bioelectronic interfaces as a powerful platform technology for high-resolution, non-invasive wearable sensing technologies.
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Affiliation(s)
- Brendan B Murphy
- Department of Bioengineering, 210 S. 33rd Street, 240 Skirkanich Hall, University of Pennsylvania, Philadelphia, PA, United States 19104
| | - Patrick J Mulcahey
- Department of Chemistry, 37th & O Streets NW, Georgetown University, Washington, DC, United States 20057
| | - Nicolette Driscoll
- Department of Bioengineering, 210 S. 33rd Street, 240 Skirkanich Hall, University of Pennsylvania, Philadelphia, PA, United States 19104
| | - Andrew G Richardson
- Center for Neuroengineering & Therapeutics, 240 S. 33rd Street, 301 Hayden Hall, University of Pennsylvania, Philadelphia, PA, United States 19104
| | - Gregory T Robbins
- Department of Physical Medicine & Rehabilitation, 1800 Lombard Street, University of Pennsylvania, Philadelphia, PA, United States 19147
| | - Nicholas V Apollo
- Center for Neuroengineering & Therapeutics, 240 S. 33rd Street, 301 Hayden Hall, University of Pennsylvania, Philadelphia, PA, United States 19104
| | - Kathleen Maleski
- Department of Materials Science and Engineering, A. J. Drexel Nanomaterials Institute, Drexel University, Philadelphia, PA, United States 19104
| | - Timothy H Lucas
- Center for Neuroengineering & Therapeutics, 240 S. 33rd Street, 301 Hayden Hall, University of Pennsylvania, Philadelphia, PA, United States 19104
| | - Yury Gogotsi
- Department of Materials Science and Engineering, A. J. Drexel Nanomaterials Institute, Drexel University, Philadelphia, PA, United States 19104
| | - Timothy Dillingham
- Department of Physical Medicine & Rehabilitation, 1800 Lombard Street, University of Pennsylvania, Philadelphia, PA, United States 19147
| | - Flavia Vitale
- Center for Neuroengineering & Therapeutics, 240 S. 33rd Street, 301 Hayden Hall, University of Pennsylvania, Philadelphia, PA, United States 19104
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Tong W, Stamp M, Apollo NV, Ganesan K, Meffin H, Prawer S, Garrett DJ, Ibbotson MR. Improved visual acuity using a retinal implant and an optimized stimulation strategy. J Neural Eng 2019; 17:016018. [DOI: 10.1088/1741-2552/ab5299] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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8
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John SE, Apollo NV, Opie NL, Rind GS, Ronayne SM, May CN, Oxley TJ, Grayden DB. In Vivo Impedance Characterization of Cortical Recording Electrodes Shows Dependence on Electrode Location and Size. IEEE Trans Biomed Eng 2018; 66:675-681. [PMID: 30004867 DOI: 10.1109/tbme.2018.2854623] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
OBJECTIVE Neural prostheses are improving the quality of life for those suffering from neurological impairments. Electrocorticography electrodes located in subdural, epidural, and intravascular positions show promise as long-term neural prostheses. However, chronic implantation affects the electrochemical environments of these arrays. METHODS In the present work, the effect of electrode location on the electrochemical properties of the interface was compared. The impedances of the electrode arrays were measured using electrochemical impedance spectroscopy in vitro in saline and in vivo four-week postimplantation. RESULTS There was not a significant effect of electrode location (subdural, intravascular, or epidural) on the impedance magnitude, and the effect of the electrode size on the impedance magnitude was frequency dependent. There was a frequency-dependent statistically significant effect of electrode location and electrode size on the phase angles of the three arrays. The subdural and epidural arrays showed phase shifts closer to -90° indicating the capacitive nature of the interface in these locations. The impact of placing electrodes within a blood vessel and adjacent to the blood vessel wall was most obvious when looking at the phase responses at frequencies below 10 kHz. CONCLUSION Our results show that intravascular electrodes, like those in subdural and epidural positions, show electrical properties that are suitable for recording. These results provide support for the use of intravascular arrays in clinically relevant neural prostheses and diagnostic devices. SIGNIFICANCE Comparison of electrochemical impedance of the epidural, intravascular, and subdural electrode array showed that all three locations are possible placement options, since impedances are in comparable ranges.
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Apollo NV, Jiang J, Cheung W, Baquier S, Lai A, Mirebedini A, Foroughi J, Wallace GG, Shivdasani MN, Prawer S, Chen S, Williams R, Cook MJ, Nayagam DAX, Garrett DJ. Development and Characterization of a Sucrose Microneedle Neural Electrode Delivery System. ACTA ACUST UNITED AC 2017. [DOI: 10.1002/adbi.201700187] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Nicholas V. Apollo
- School of Physics; University of Melbourne; Parkville Victoria 3010 Australia
- The Bionics Institute; 384-388 Albert St. East Melbourne Victoria 3002 Australia
| | - Jonathan Jiang
- Department of Medicine; University of Melbourne; Parkville Victoria 3010 Australia
| | - Warwick Cheung
- Department of Medicine; University of Melbourne; Parkville Victoria 3010 Australia
| | - Sebastien Baquier
- Department of Medicine; University of Melbourne; Parkville Victoria 3010 Australia
- Faculty of Veterinary and Agricultural Sciences; University of Melbourne; Parkville Victoria 3010 Australia
| | - Alan Lai
- Department of Medicine; University of Melbourne; Parkville Victoria 3010 Australia
| | - Azadeh Mirebedini
- Intelligent Polymer Research Institute (IPRI); AIIM Facility; Innovation Campus; University of Wollongong; Wollongong New South Wales 2522 Australia
| | - Javad Foroughi
- Intelligent Polymer Research Institute (IPRI); AIIM Facility; Innovation Campus; University of Wollongong; Wollongong New South Wales 2522 Australia
| | - Gordon G. Wallace
- Intelligent Polymer Research Institute (IPRI); AIIM Facility; Innovation Campus; University of Wollongong; Wollongong New South Wales 2522 Australia
| | - Mohit N. Shivdasani
- The Bionics Institute; 384-388 Albert St. East Melbourne Victoria 3002 Australia
- Department of Medical Bionics; University of Melbourne; Parkville Victoria 3010 Australia
| | - Steven Prawer
- School of Physics; University of Melbourne; Parkville Victoria 3010 Australia
| | - Shou Chen
- Department of Anatomical Pathology; St Vincent's Hospital Melbourne; Fitzroy Victoria 3065 Australia
| | - Richard Williams
- Department of Anatomical Pathology; St Vincent's Hospital Melbourne; Fitzroy Victoria 3065 Australia
- Department of Pathology; University of Melbourne; Parkville Victoria 3010 Australia
| | - Mark J. Cook
- Department of Medicine; University of Melbourne; Parkville Victoria 3010 Australia
| | - David A. X. Nayagam
- The Bionics Institute; 384-388 Albert St. East Melbourne Victoria 3002 Australia
- Department of Pathology; University of Melbourne; Parkville Victoria 3010 Australia
| | - David J. Garrett
- School of Physics; University of Melbourne; Parkville Victoria 3010 Australia
- The Bionics Institute; 384-388 Albert St. East Melbourne Victoria 3002 Australia
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Ahnood A, Meffin H, Garrett DJ, Fox K, Ganesan K, Stacey A, Apollo NV, Wong YT, Lichter SG, Kentler W, Kavehei O, Greferath U, Vessey KA, Ibbotson MR, Fletcher EL, Burkitt AN, Prawer S. Diamond Devices for High Acuity Prosthetic Vision. ACTA ACUST UNITED AC 2016; 1:e1600003. [DOI: 10.1002/adbi.201600003] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Revised: 10/27/2016] [Indexed: 12/17/2022]
Affiliation(s)
- Arman Ahnood
- School of Physics University of Melbourne Victoria 3010 Australia
| | - Hamish Meffin
- National Vision Research Institute Australian College of Optometry Victoria 3053 Australia
- ARC Centre of Excellence for Integrative Brain Function Department of Optometry and Vision Science University of Melbourne Victoria 3010 Australia
| | - David J. Garrett
- School of Physics University of Melbourne Victoria 3010 Australia
| | - Kate Fox
- School of Physics University of Melbourne Victoria 3010 Australia
- School of Engineering RMIT University Melbourne 3000 Australia
| | | | - Alastair Stacey
- School of Physics University of Melbourne Victoria 3010 Australia
| | | | - Yan T. Wong
- National Vision Research Institute Australian College of Optometry Victoria 3053 Australia
- Department of Electrical & Electronic Engineering The University of Melbourne Victoria 3010 Australia
| | | | - William Kentler
- Department of Electrical & Electronic Engineering The University of Melbourne Victoria 3010 Australia
| | - Omid Kavehei
- School of Engineering RMIT University Melbourne 3000 Australia
| | - Ursula Greferath
- Department of Anatomy and Neuroscience University of Melbourne Victoria 3010 Australia
| | - Kirstan A. Vessey
- Department of Anatomy and Neuroscience University of Melbourne Victoria 3010 Australia
| | - Michael R. Ibbotson
- National Vision Research Institute Australian College of Optometry Victoria 3053 Australia
- ARC Centre of Excellence for Integrative Brain Function Department of Optometry and Vision Science University of Melbourne Victoria 3010 Australia
| | - Erica L. Fletcher
- Department of Anatomy and Neuroscience University of Melbourne Victoria 3010 Australia
| | - Anthony N. Burkitt
- Department of Electrical & Electronic Engineering The University of Melbourne Victoria 3010 Australia
| | - Steven Prawer
- School of Physics University of Melbourne Victoria 3010 Australia
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Maturana MI, Apollo NV, Garrett DJ, Kameneva T, Meffin H, Ibbotson MR, Cloherty SL, Grayden DB. The effects of temperature changes on retinal ganglion cell responses to electrical stimulation. Annu Int Conf IEEE Eng Med Biol Soc 2016; 2015:7506-9. [PMID: 26738028 DOI: 10.1109/embc.2015.7320128] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Little is known about how the retina's response to electrical stimulation is modified by temperatures. In vitro experiments are often used to inform in vivo studies, hence it is important to understand what changes occur at physiological temperature. To investigate this, we recorded from eight RGCs in vitro at three temperatures; room temperature (24°C), 30°C and 34°C. Results show that response latencies and thresholds are reduced, bursting spike rates in response to stimulation increases, and the spiking becomes more consistently locked to the stimulus at higher temperatures.
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Maturana MI, Apollo NV, Hadjinicolaou AE, Garrett DJ, Cloherty SL, Kameneva T, Grayden DB, Ibbotson MR, Meffin H. A Simple and Accurate Model to Predict Responses to Multi-electrode Stimulation in the Retina. PLoS Comput Biol 2016; 12:e1004849. [PMID: 27035143 PMCID: PMC4818105 DOI: 10.1371/journal.pcbi.1004849] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Accepted: 03/04/2016] [Indexed: 11/19/2022] Open
Abstract
Implantable electrode arrays are widely used in therapeutic stimulation of the nervous system (e.g. cochlear, retinal, and cortical implants). Currently, most neural prostheses use serial stimulation (i.e. one electrode at a time) despite this severely limiting the repertoire of stimuli that can be applied. Methods to reliably predict the outcome of multi-electrode stimulation have not been available. Here, we demonstrate that a linear-nonlinear model accurately predicts neural responses to arbitrary patterns of stimulation using in vitro recordings from single retinal ganglion cells (RGCs) stimulated with a subretinal multi-electrode array. In the model, the stimulus is projected onto a low-dimensional subspace and then undergoes a nonlinear transformation to produce an estimate of spiking probability. The low-dimensional subspace is estimated using principal components analysis, which gives the neuron’s electrical receptive field (ERF), i.e. the electrodes to which the neuron is most sensitive. Our model suggests that stimulation proportional to the ERF yields a higher efficacy given a fixed amount of power when compared to equal amplitude stimulation on up to three electrodes. We find that the model captures the responses of all the cells recorded in the study, suggesting that it will generalize to most cell types in the retina. The model is computationally efficient to evaluate and, therefore, appropriate for future real-time applications including stimulation strategies that make use of recorded neural activity to improve the stimulation strategy. Implantable multi-electrode arrays (MEAs) are used to record neurological signals and stimulate the nervous system to restore lost function (e.g. cochlear implants). MEAs that can combine both sensing and stimulation will revolutionize the development of the next generation of devices. Simple models that can accurately characterize neural responses to electrical stimulation are necessary for the development of future neuroprostheses controlled by neural feedback. We demonstrate a model that accurately predicts neural responses to concurrent stimulation across multiple electrodes. The model is simple to evaluate, making it an appropriate model for use with neural feedback. The methods described are applicable to a wide range of neural prostheses, thus greatly assisting future device development.
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Affiliation(s)
- Matias I. Maturana
- National Vision Research Institute, Australian College of Optometry, Carlton, Victoria, Australia
- Department of Electrical and Electronic Engineering, NeuroEngineering Laboratory, University of Melbourne, Parkville, Victoria, Australia
| | - Nicholas V. Apollo
- Department of Physics, University of Melbourne, Parkville, Victoria, Australia
| | - Alex E. Hadjinicolaou
- National Vision Research Institute, Australian College of Optometry, Carlton, Victoria, Australia
| | - David J. Garrett
- Department of Physics, University of Melbourne, Parkville, Victoria, Australia
| | - Shaun L. Cloherty
- National Vision Research Institute, Australian College of Optometry, Carlton, Victoria, Australia
- Department of Electrical and Electronic Engineering, NeuroEngineering Laboratory, University of Melbourne, Parkville, Victoria, Australia
- Department of Optometry and Vision Sciences, ARC Centre of Excellence for Integrative Brain Function, University of Melbourne, Parkville, Victoria, Australia
| | - Tatiana Kameneva
- Department of Electrical and Electronic Engineering, NeuroEngineering Laboratory, University of Melbourne, Parkville, Victoria, Australia
| | - David B. Grayden
- Department of Electrical and Electronic Engineering, NeuroEngineering Laboratory, University of Melbourne, Parkville, Victoria, Australia
- Centre for Neural Engineering, University of Melbourne, Parkville, Victoria, Australia
| | - Michael R. Ibbotson
- National Vision Research Institute, Australian College of Optometry, Carlton, Victoria, Australia
- Department of Optometry and Vision Sciences, ARC Centre of Excellence for Integrative Brain Function, University of Melbourne, Parkville, Victoria, Australia
| | - Hamish Meffin
- National Vision Research Institute, Australian College of Optometry, Carlton, Victoria, Australia
- Department of Optometry and Vision Sciences, ARC Centre of Excellence for Integrative Brain Function, University of Melbourne, Parkville, Victoria, Australia
- * E-mail:
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Fox K, Meffin H, Burns O, Abbott CJ, Allen PJ, Opie NL, McGowan C, Yeoh J, Ahnood A, Luu CD, Cicione R, Saunders AL, McPhedran M, Cardamone L, Villalobos J, Garrett DJ, Nayagam DAX, Apollo NV, Ganesan K, Shivdasani MN, Stacey A, Escudie M, Lichter S, Shepherd RK, Prawer S. Development of a Magnetic Attachment Method for Bionic Eye Applications. Artif Organs 2015; 40:E12-24. [DOI: 10.1111/aor.12582] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Kate Fox
- School of Physics; University of Melbourne; Melbourne Victoria Australia
- School of Aerospace, Mechanical and Manufacturing Engineering; RMIT University; Melbourne Victoria Australia
| | - Hamish Meffin
- Department of Electrical and Electronic Engineering; University of Melbourne; Melbourne Victoria Australia
- National Vision Research Institute; Australian College of Optometry; Melbourne Victoria Australia
| | - Owen Burns
- The Bionics Institute; Melbourne Victoria Australia
| | - Carla J. Abbott
- Centre for Eye Research Australia (CERA) Royal Victorian Eye and Ear Hospital; Melbourne Victoria Australia
| | - Penelope J. Allen
- Centre for Eye Research Australia (CERA) Royal Victorian Eye and Ear Hospital; Melbourne Victoria Australia
| | - Nicholas L. Opie
- Centre for Eye Research Australia (CERA) Royal Victorian Eye and Ear Hospital; Melbourne Victoria Australia
| | | | - Jonathan Yeoh
- Centre for Eye Research Australia (CERA) Royal Victorian Eye and Ear Hospital; Melbourne Victoria Australia
| | - Arman Ahnood
- School of Physics; University of Melbourne; Melbourne Victoria Australia
| | - Chi D. Luu
- Centre for Eye Research Australia (CERA) Royal Victorian Eye and Ear Hospital; Melbourne Victoria Australia
| | - Rosemary Cicione
- School of Physics; University of Melbourne; Melbourne Victoria Australia
| | | | | | | | | | - David J. Garrett
- School of Physics; University of Melbourne; Melbourne Victoria Australia
- The Bionics Institute; Melbourne Victoria Australia
| | | | - Nicholas V. Apollo
- School of Physics; University of Melbourne; Melbourne Victoria Australia
- The Bionics Institute; Melbourne Victoria Australia
| | - Kumaravelu Ganesan
- School of Physics; University of Melbourne; Melbourne Victoria Australia
| | | | - Alastair Stacey
- School of Physics; University of Melbourne; Melbourne Victoria Australia
| | - Mathilde Escudie
- School of Physics; University of Melbourne; Melbourne Victoria Australia
| | - Samantha Lichter
- School of Physics; University of Melbourne; Melbourne Victoria Australia
| | | | - Steven Prawer
- School of Physics; University of Melbourne; Melbourne Victoria Australia
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14
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Lichter SG, Escudié MC, Stacey AD, Ganesan K, Fox K, Ahnood A, Apollo NV, Kua DC, Lee AZ, McGowan C, Saunders AL, Burns O, Nayagam DAX, Williams RA, Garrett DJ, Meffin H, Prawer S. Hermetic diamond capsules for biomedical implants enabled by gold active braze alloys. Biomaterials 2015; 53:464-74. [PMID: 25890743 DOI: 10.1016/j.biomaterials.2015.02.103] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Revised: 02/23/2015] [Accepted: 02/24/2015] [Indexed: 11/19/2022]
Abstract
As the field of biomedical implants matures the functionality of implants is rapidly increasing. In the field of neural prostheses this is particularly apparent as researchers strive to build devices that interact with highly complex neural systems such as vision, hearing, touch and movement. A retinal implant, for example, is a highly complex device and the surgery, training and rehabilitation requirements involved in deploying such devices are extensive. Ideally, such devices will be implanted only once and will continue to function effectively for the lifetime of the patient. The first and most pivotal factor that determines device longevity is the encapsulation that separates the sensitive electronics of the device from the biological environment. This paper describes the realisation of a free standing device encapsulation made from diamond, the most impervious, long lasting and biochemically inert material known. A process of laser micro-machining and brazing is described detailing the fabrication of hermetic electrical feedthroughs and laser weldable seams using a 96.4% gold active braze alloy, another material renowned for biochemical longevity. Accelerated ageing of the braze alloy, feedthroughs and hermetic capsules yielded no evidence of corrosion and no loss of hermeticity. Samples of the gold braze implanted for 15 weeks, in vivo, caused minimal histopathological reaction and results were comparable to those obtained from medical grade silicone controls. The work described represents a first account of a free standing, fully functional hermetic diamond encapsulation for biomedical implants, enabled by gold active alloy brazing and laser micro-machining.
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Affiliation(s)
- Samantha G Lichter
- School of Physics, The University of Melbourne, Victoria 3010, Australia
| | - Mathilde C Escudié
- School of Physics, The University of Melbourne, Victoria 3010, Australia
| | - Alastair D Stacey
- School of Physics, The University of Melbourne, Victoria 3010, Australia
| | - Kumaravelu Ganesan
- School of Physics, The University of Melbourne, Victoria 3010, Australia
| | - Kate Fox
- School of Aerospace, Mechanical and Manufacturing Engineering, RMIT University, Victoria 3001, Australia
| | - Arman Ahnood
- School of Physics, The University of Melbourne, Victoria 3010, Australia
| | - Nicholas V Apollo
- School of Physics, The University of Melbourne, Victoria 3010, Australia
| | - Dunstan C Kua
- School of Physics, The University of Melbourne, Victoria 3010, Australia; Department of Materials Engineering, Faculty of Engineering, Monash University, Victoria 3800, Australia
| | - Aaron Z Lee
- School of Physics, The University of Melbourne, Victoria 3010, Australia; Department of Materials Engineering, Faculty of Engineering, Monash University, Victoria 3800, Australia
| | - Ceara McGowan
- The Bionics Institute, 384-388 Albert Street, East Melbourne, Victoria 3002, Australia
| | - Alexia L Saunders
- The Bionics Institute, 384-388 Albert Street, East Melbourne, Victoria 3002, Australia
| | - Owen Burns
- The Bionics Institute, 384-388 Albert Street, East Melbourne, Victoria 3002, Australia
| | - David A X Nayagam
- The Bionics Institute, 384-388 Albert Street, East Melbourne, Victoria 3002, Australia; Department of Pathology, The University of Melbourne, Victoria 3010, Australia
| | - Richard A Williams
- National Vision Research Institute, Department of Optometry and Vision Sciences, University of Melbourne, Victoria 3010, Australia; Department of Anatomical Pathology, St Vincent's Hospital, Fitzroy, Victoria 3065, Australia
| | - David J Garrett
- School of Physics, The University of Melbourne, Victoria 3010, Australia; The Bionics Institute, 384-388 Albert Street, East Melbourne, Victoria 3002, Australia.
| | - Hamish Meffin
- National Vision Research Institute, Department of Optometry and Vision Sciences, University of Melbourne, Victoria 3010, Australia
| | - Steven Prawer
- School of Physics, The University of Melbourne, Victoria 3010, Australia
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Opie NL, Ayton LN, Apollo NV, Ganesan K, Guymer RH, Luu CD. Optical Coherence Tomography-Guided Retinal Prosthesis Design: Model of Degenerated Retinal Curvature and Thickness for Patient-Specific Devices. Artif Organs 2014; 38:E82-94. [DOI: 10.1111/aor.12287] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Nicholas L. Opie
- Centre for Eye Research Australia; Royal Victorian Eye and Ear Hospital; The University of Melbourne; Melbourne Victoria Australia
| | - Lauren N. Ayton
- Centre for Eye Research Australia; Royal Victorian Eye and Ear Hospital; The University of Melbourne; Melbourne Victoria Australia
| | - Nicholas V. Apollo
- Melbourne Materials Institute; Department of Physics; The University of Melbourne; Melbourne Victoria Australia
| | - Kumaravelu Ganesan
- Melbourne Materials Institute; Department of Physics; The University of Melbourne; Melbourne Victoria Australia
| | - Robyn H. Guymer
- Centre for Eye Research Australia; Royal Victorian Eye and Ear Hospital; The University of Melbourne; Melbourne Victoria Australia
| | - Chi D. Luu
- Centre for Eye Research Australia; Royal Victorian Eye and Ear Hospital; The University of Melbourne; Melbourne Victoria Australia
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Ayton LN, Apollo NV, Varsamidis M, Dimitrov PN, Guymer RH, Luu CD. Assessing residual visual function in severe vision loss. Invest Ophthalmol Vis Sci 2014; 55:1332-8. [PMID: 24481260 DOI: 10.1167/iovs.13-12657] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE Vision restoration is a fast-approaching reality for some people with profound vision loss. In order to reliably determine treatment efficacy, accurate assessment of baseline residual visual function is critical. The purpose of this study was to compare residual function as detected on Goldman visual field (GVF) and full-field ERG (ffERG), and correlate with the remaining photoreceptor layer as determined by spectral-domain optical coherence tomography (SD-OCT), in subjects with severe vision loss. METHODS Fifty-four subjects with advanced retinitis pigmentosa and no discernible signal on ffERG were included. Trace residual function was assessed using discrete Fourier transform (DFT) analysis of the 30-Hz flicker ffERG and the percentage of remaining GVF. The horizontal extent of the outer nuclear layer (ONL) on SD-OCT was assessed. RESULTS Thirty percent of the study eyes had a 30-Hz flicker response after DFT analysis of the ffERG, and 57% had a measurable GVF. Thirty-five percent had a visible ONL on SD-OCT. There was no significant correlation between the magnitude of the 30-Hz flicker response and the percentage of remaining GVF (r = 0.172, P = 0.213) or the extent of remaining central photoreceptors (r = 0.258, P = 0.06). Only 17% of the eyes had all three parameters detected. CONCLUSIONS Discrete Fourier transform analysis of the 30Hz-flicker ffERG response and GVF can detect trace residual function. Evidence of this residual function is not always supported by the structural correlate of a measurable ONL. Our findings highlight the importance of completing a multimodal assessment to accurately define the important parameters of retinal structure and function in people with profound vision loss.
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Affiliation(s)
- Lauren N Ayton
- Centre for Eye Research Australia, The University of Melbourne, Royal Victorian Eye and Ear Hospital, East Melbourne, Victoria, Australia
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