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Schreib CC, Jarvis MI, Terlier T, Goell J, Mukherjee S, Doerfert MD, Wilson TA, Beauregard M, Martins KN, Lee J, Solis LS, Vazquez E, Oberli MA, Hanak BW, Diehl M, Hilton I, Veiseh O. Lipid Deposition Profiles Influence Foreign Body Responses. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2205709. [PMID: 36871193 PMCID: PMC10309593 DOI: 10.1002/adma.202205709] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Revised: 12/09/2022] [Indexed: 05/26/2023]
Abstract
Fibrosis remains a significant cause of failure in implanted biomedical devices and early absorption of proteins on implant surfaces has been shown to be a key instigating factor. However, lipids can also regulate immune activity and their presence may also contribute to biomaterial-induced foreign body responses (FBR) and fibrosis. Here it is demonstrated that the surface presentation of lipids on implant affects FBR by influencing reactions of immune cells to materials as well as their resultant inflammatory/suppressive polarization. Time-of-flight secondary ion mass spectroscopy (ToF-SIMS) is employed to characterize lipid deposition on implants that are surface-modified chemically with immunomodulatory small molecules. Multiple immunosuppressive phospholipids (phosphatidylcholine, phosphatidylinositol, phosphatidylethanolamine, and sphingomyelin) are all found to deposit preferentially on implants with anti-FBR surface modifications in mice. Significantly, a set of 11 fatty acids is enriched on unmodified implanted devices that failed in both mice and humans, highlighting relevance across species. Phospholipid deposition is also found to upregulate the transcription of anti-inflammatory genes in murine macrophages, while fatty acid deposition stimulated the expression of pro-inflammatory genes. These results provide further insights into how to improve the design of biomaterials and medical devices to mitigate biomaterial material-induced FBR and fibrosis.
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Affiliation(s)
- Christian C. Schreib
- Department of Bioengineering, Rice University, 6500 Main Street, Houston, TX 77030
| | - Maria I. Jarvis
- Department of Bioengineering, Rice University, 6500 Main Street, Houston, TX 77030
- Present address: Lonza Inc. 14905 Kirby Drive, Houston, TX 77047
| | - Tanguy Terlier
- SIMS laboratory, Shared Equipment Authority, Rice University, 6500 Main Street, Houston, TX 77030
| | - Jacob Goell
- Department of Bioengineering, Rice University, 6500 Main Street, Houston, TX 77030
| | - Sudip Mukherjee
- Department of Bioengineering, Rice University, 6500 Main Street, Houston, TX 77030
- Present address: School of Biomedial Engineering, ITT (BHU), Varanasi 221005, Uttar Pradesh, India
| | - Michael D. Doerfert
- Department of Bioengineering, Rice University, 6500 Main Street, Houston, TX 77030
| | - Taylor Anne Wilson
- Department of Neurosurgery, Loma Linda University Health, 11234 Anderson St, Loma Linda, CA 92354
| | - Michael Beauregard
- Department of Bioengineering, Rice University, 6500 Main Street, Houston, TX 77030
| | - Kevin N. Martins
- Department of Neurosurgery, Loma Linda University Health, 11234 Anderson St, Loma Linda, CA 92354
| | - Jared Lee
- Department of Chemistry, Rice University, 6100 Main St, Houston, TX 77005
| | - Leo Sanchez Solis
- Department of Bioengineering, Rice University, 6500 Main Street, Houston, TX 77030
| | - Esperanza Vazquez
- Department of Biomedical Engineering, University of Houston, 3517 Cullen Blvd, Houston, TX 77204
| | - Matthias A. Oberli
- Sigilon Therapeutics, 200 Dexter Avenue, Watertown, MA 02472
- Present address: Xibus systems Inc. 200 Dexter Avenue, Watertown, MA 02472
| | - Brian W. Hanak
- Department of Neurosurgery, Loma Linda University Health, 11234 Anderson St, Loma Linda, CA 92354
| | - Michael Diehl
- Department of Bioengineering, Rice University, 6500 Main Street, Houston, TX 77030
| | - Isaac Hilton
- Department of Bioengineering, Rice University, 6500 Main Street, Houston, TX 77030
- Program of Synthetic, Systems and Physical Biology, Rice University, 6500 Main Street, Houston, TX 77030
| | - Omid Veiseh
- Department of Bioengineering, Rice University, 6500 Main Street, Houston, TX 77030
- Program of Synthetic, Systems and Physical Biology, Rice University, 6500 Main Street, Houston, TX 77030
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Kumar V, Yu C, McGinn CK, Perks KE, Thompson SM, Sawtell NB, Kymissis I. A Dense Conformal Electrode Array for High Spatial Resolution Stimulation of Electrosensory Systems. ADVANCED MATERIALS TECHNOLOGIES 2023; 8:2200354. [PMID: 37007916 PMCID: PMC10062704 DOI: 10.1002/admt.202200354] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Indexed: 06/19/2023]
Abstract
Studies of electrosensory systems have led to insights into to a number of general issues in biology. However, investigations of these systems have been limited by the inability to precisely control spatial patterns of electrosensory input. In this paper, an electrode array and a system to selectively stimulate spatially restricted regions of an electroreceptor array is presented. The array has 96 channels consisting of chrome/gold electrodes patterned on a flexible parylene-C substrate and encapsulated with another parylene-C layer. The conformability of the electrode array allows for optimal current driving and surface interface conditions. Recordings of neural activity at the first central processing stage in weakly electric mormyrid fish support the potential of this system for high spatial resolution stimulation and mapping of electrosensory systems.
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Affiliation(s)
- Vikrant Kumar
- Department of Electrical Engineering, Columbia University, New York, NY 10027, USA
| | - Caroline Yu
- Department of Electrical Engineering, Columbia University, New York, NY 10027, USA
| | - Christine K McGinn
- Department of Electrical Engineering, Columbia University, New York, NY 10027, USA
| | - Krista E Perks
- Department of Neuroscience, Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA
| | - Sarah M Thompson
- Department of Electrical Engineering, Columbia University, New York, NY 10027, USA
| | - Nathaniel B Sawtell
- Department of Neuroscience, Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA
| | - Ioannis Kymissis
- Department of Electrical Engineering, Columbia University, New York, NY 10027, USA
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Khatoun A, Asamoah B, Mc Laughlin M. A Computational Modeling Study to Investigate the Use of Epicranial Electrodes to Deliver Interferential Stimulation to Subcortical Regions. Front Neurosci 2022; 15:779271. [PMID: 34975383 PMCID: PMC8716464 DOI: 10.3389/fnins.2021.779271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2021] [Accepted: 11/29/2021] [Indexed: 11/16/2022] Open
Abstract
Background: Epicranial cortical stimulation (ECS) is a minimally invasive neuromodulation technique that works by passing electric current between subcutaneous electrodes positioned on the skull. ECS causes a stronger and more focused electric field in the cortex compared to transcranial electric stimulation (TES) where the electrodes are placed on the scalp. However, it is unknown if ECS can target deeper regions where the electric fields become relatively weak and broad. Recently, interferential stimulation (IF) using scalp electrodes has been proposed as a novel technique to target subcortical regions. During IF, two high, but slightly different, frequencies are applied which sum to generate a low frequency field (i.e., 10 Hz) at a target subcortical region. We hypothesized that IF using ECS electrodes would cause stronger and more focused subcortical stimulation than that using TES electrodes. Objective: Use computational modeling to determine if interferential stimulation-epicranial cortical stimulation (IF-ECS) can target subcortical regions. Then, compare the focality and field strength of IF-ECS to that of interferential Stimulation-transcranial electric stimulation (IF-TES) in the same subcortical region. Methods: A human head computational model was developed with 19 TES and 19 ECS disk electrodes positioned on a 10–20 system. After tetrahedral mesh generation the model was imported to COMSOL where the electric field distribution was calculated for each electrode separately. Then in MATLAB, subcortical targets were defined and the optimal configurations were calculated for both the TES and ECS electrodes. Results: Interferential stimulation using ECS electrodes can deliver stronger and more focused electric fields to subcortical regions than IF using TES electrodes. Conclusion: Interferential stimulation combined with ECS is a promising approach for delivering subcortical stimulation without the need for a craniotomy.
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Affiliation(s)
- Ahmad Khatoun
- ExpORL, Department of Neurosciences, KU Leuven, Leuven, Belgium.,The Leuven Brain Institute, KU Leuven, Leuven, Belgium
| | - Boateng Asamoah
- ExpORL, Department of Neurosciences, KU Leuven, Leuven, Belgium.,The Leuven Brain Institute, KU Leuven, Leuven, Belgium
| | - Myles Mc Laughlin
- ExpORL, Department of Neurosciences, KU Leuven, Leuven, Belgium.,The Leuven Brain Institute, KU Leuven, Leuven, Belgium
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Dauzon E, Sallenave X, Plesse C, Goubard F, Amassian A, Anthopoulos TD. Pushing the Limits of Flexibility and Stretchability of Solar Cells: A Review. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021; 33:e2101469. [PMID: 34297433 DOI: 10.1002/adma.202101469] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Revised: 04/25/2021] [Indexed: 06/13/2023]
Abstract
Emerging forms of soft, flexible, and stretchable electronics promise to revolutionize the electronics industries of the future offering radically new products that combine multiple functionalities, including power generation, with arbitrary form factor. For example, skin-like electronics promise to transform the human-machine-interface, but the softness of the skin is incompatible with traditional electronic components. To address this issue, new strategies toward soft and wearable electronic systems are currently being pursued, which also include stretchable photovoltaics as self-powering systems for use in autonomous and stretchable electronics of the future. Here recent developments in the field of stretchable photovoltaics are reviewed and their potential for various emerging applications are examined. Emphasis is placed on the different strategies to induce stretchability including extrinsic and intrinsic approaches. In the former case, engineering and patterning of the materials and devices are key elements while intrinsically stretchable systems rely on mechanically compliant materials such as elastomers and organic conjugated polymers. The result is a review article that provides a comprehensive summary of the progress to date in the field of stretchable solar cells from the nanoscale to macroscopic functional devices. The article is concluded by discussing the emerging trends and future developments.
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Affiliation(s)
- Emilie Dauzon
- King Abdullah University of Science and Technology (KAUST), KAUST Solar Centre (KSC), Physical Science and Engineering Division, Thuwal, 23955-6900, Saudi Arabia
| | | | - Cedric Plesse
- LPPI, CY Cergy Paris Université, Cergy, 95000, France
| | | | - Aram Amassian
- Department of Materials Science and Engineering, and Organic and Carbon Electronic Laboratories (ORaCEL), North Carolina State University, Raleigh, NC, 27695, USA
| | - Thomas D Anthopoulos
- King Abdullah University of Science and Technology (KAUST), KAUST Solar Centre (KSC), Physical Science and Engineering Division, Thuwal, 23955-6900, Saudi Arabia
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Qi D, Zhang K, Tian G, Jiang B, Huang Y. Stretchable Electronics Based on PDMS Substrates. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021; 33:e2003155. [PMID: 32830370 DOI: 10.1002/adma.202003155] [Citation(s) in RCA: 129] [Impact Index Per Article: 43.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2020] [Revised: 06/05/2020] [Indexed: 05/27/2023]
Abstract
Stretchable electronics, which can retain their functions under stretching, have attracted great interest in recent decades. Elastic substrates, which bear the applied strain and regulate the strain distribution in circuits, are indispensable components in stretchable electronics. Moreover, the self-healing property of the substrate is a premise to endow stretchable electronics with the same characteristics, so the device may recover from failure resulting from large and frequent deformations. Therefore, the properties of the elastic substrate are crucial to the overall performance of stretchable devices. Poly(dimethylsiloxane) (PDMS) is widely used as the substrate material for stretchable electronics, not only because of its advantages, which include stable chemical properties, good thermal stability, transparency, and biological compatibility, but also because of its capability of attaining designer functionalities via surface modification and bulk property tailoring. Herein, the strategies for fabricating stretchable electronics on PDMS substrates are summarized, and the influence of the physical and chemical properties of PDMS, including surface chemical status, physical modulus, geometric structures, and self-healing properties, on the performance of stretchable electronics is discussed. Finally, the challenges and future opportunities of stretchable electronics based on PDMS substrates are considered.
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Affiliation(s)
- Dianpeng Qi
- MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage, School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin, 150001, China
| | - Kuiyuan Zhang
- MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage, School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin, 150001, China
| | - Gongwei Tian
- MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage, School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin, 150001, China
| | - Bo Jiang
- MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage, School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin, 150001, China
| | - Yudong Huang
- MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage, School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin, 150001, China
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Flexible Electrocorticography Electrode Array for Epileptiform Electrical Activity Recording under Glutamate and GABA Modulation on the Primary Somatosensory Cortex of Rats. MICROMACHINES 2020; 11:mi11080732. [PMID: 32751055 PMCID: PMC7465452 DOI: 10.3390/mi11080732] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 07/23/2020] [Accepted: 07/24/2020] [Indexed: 12/11/2022]
Abstract
Epilepsy is a common neurological disorder. There is still a lack of methods to accurately detect cortical activity and locate lesions. In this work, a flexible electrocorticography (ECoG) electrode array based on polydimethylsiloxane (PDMS)-parylene was fabricated to detect epileptiform activity under glutamate (Glu) and gamma-aminobutyric acid (GABA) modulation on primary somatosensory cortex of rats. The electrode with a thickness of 20 μm has good flexibility to establish reliable contact with the cortex. Fourteen recording sites with a diameter of 60 μm are modified by electroplating platinum black nanoparticles, which effectively improve the performance with lower impedance, obtaining a sensitive sensing interface. The electrode enables real-time capturing changes in neural activity under drug modulation. Under Glu modulation, neuronal populations showed abnormal excitability, manifested as hypsarrhythmia rhythm and continuous or periodic spike wave epileptiform activity, with power increasing significantly. Under GABA modulation, the excitement was inhibited, with amplitude and power reduced to normal. The flexible ECoG electrode array could monitor cortical activity, providing us with an effective tool for further studying epilepsy and locating lesions.
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Kang PL, Lin YH, Settu K, Yen CS, Yeh CY, Liu JT, Chen CJ, Chang SJ. A Facile Fabrication of Biodegradable and Biocompatible Cross-Linked Gelatin as Screen Printing Substrates. Polymers (Basel) 2020; 12:polym12051186. [PMID: 32456005 PMCID: PMC7284702 DOI: 10.3390/polym12051186] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Revised: 05/15/2020] [Accepted: 05/19/2020] [Indexed: 01/06/2023] Open
Abstract
This study focuses on preparation and valuation of the biodegradable, native, and modified gelatin film as screen-printing substrates. Modified gelatin film was prepared by crosslinking with various crosslinking agents and the electrode array was designed by screen-printing. It was observed that the swelling ratio of C-2, crosslinked with glutaraldehyde and EDC/NHS (1-ethyl-3-(3-dimethylaminopropyl) carbodiimide/N-hydroxysuccinimide) was found to be lower (3.98%) than that of C-1 (crosslinked with only glutaraldehyde) (8.77%) and C-0 (without crosslinking) (28.15%). The obtained results indicate that the swelling ratios of both C-1 and C-2 were found to be lower than that of C-0 (control one without crosslinking). The Young's modulus for C-1 and C-2 was found to be 8.55 ± 0.57 and 23.72 ± 2.04 kPa, respectively. Hence, it was conveyed that the mechanical strength of C-2 was found to be two times higher than that of C-l, suggesting that the mechanical strength was enhanced upon dual crosslinking in this study also. The adhesion study indicates that silver ink adhesion on the gelation surface is better than that of carbon ink. In addition, the electrical response of C-2 with a screen-printed electrode (SPE) was found to be the same as the commercial polycarbonate (PC) substrate. The result of MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) assay suggested that the silver SPE on C-2 was non-cytotoxic toward L929 fibroblast cells proliferation. The results indicated that C-2 gelatin is a promising material to act as a screen-printing substrate with excellent biodegradable and biocompatible properties.
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Affiliation(s)
- Pei-Leun Kang
- Cardiovascular Surgery, Department of Surgery, Kaohsiung Veterans General Hospital, Kaohsiung 81362, Taiwan; (P.-L.K.); (Y.-H.L.)
| | - Yu-Hsin Lin
- Cardiovascular Surgery, Department of Surgery, Kaohsiung Veterans General Hospital, Kaohsiung 81362, Taiwan; (P.-L.K.); (Y.-H.L.)
| | - Kalpana Settu
- Department of Electrical Engineering, National Taipei University, New Taipei 23741, Taiwan;
| | - Ching-Shu Yen
- Department of Biomedical Engineering, I-Shou University, Kaohsiung 82445, Taiwan; (C.-S.Y.); (C.-Y.Y.)
| | - Chin-Yi Yeh
- Department of Biomedical Engineering, I-Shou University, Kaohsiung 82445, Taiwan; (C.-S.Y.); (C.-Y.Y.)
| | - Jen-Tsai Liu
- College of Materials Science and Opto-Electronic Technology, University of Chinese Academy of Sciences, Beijing 100049, China
- Correspondence: (J.-T.L.); (C.-J.C.); (S.-J.C.); Tel.: +886-76151100-7467 (S.-J.C.)
| | - Ching-Jung Chen
- School of Opto-Electronic Technology, University of Chinese Academy of Sciences, Beijing 100049, China
- Correspondence: (J.-T.L.); (C.-J.C.); (S.-J.C.); Tel.: +886-76151100-7467 (S.-J.C.)
| | - Shwu-Jen Chang
- Department of Biomedical Engineering, I-Shou University, Kaohsiung 82445, Taiwan; (C.-S.Y.); (C.-Y.Y.)
- Correspondence: (J.-T.L.); (C.-J.C.); (S.-J.C.); Tel.: +886-76151100-7467 (S.-J.C.)
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Cutrone A, Micera S. Implantable Neural Interfaces and Wearable Tactile Systems for Bidirectional Neuroprosthetics Systems. Adv Healthc Mater 2019; 8:e1801345. [PMID: 31763784 DOI: 10.1002/adhm.201801345] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Revised: 03/22/2019] [Indexed: 12/12/2022]
Abstract
Neuroprosthetics and neuromodulation represent a promising field for several related applications in the central and peripheral nervous system, such as the treatment of neurological disorders, the control of external robotic devices, and the restoration of lost tactile functions. These actions are allowed by the neural interface, a miniaturized implantable device that most commonly exploits electrical energy to fulfill these operations. A neural interface must be biocompatible, stable over time, low invasive, and highly selective; the challenge is to develop a safe, compact, and reliable tool for clinical applications. In case of anatomical impairments, neuroprosthetics is bound to the need of exploring the surrounding environment by fast-responsive and highly sensitive artificial tactile sensors that mimic the natural sense of touch. Tactile sensors and neural interfaces are closely interconnected since the readouts from the first are required to convey information to the neural implantable apparatus. The role of these devices is pivotal hence technical improvements are essential to ensure a secure system to be eventually adopted in daily life. This review highlights the fundamental criteria for the design and microfabrication of neural interfaces and artificial tactile sensors, their use in clinical applications, and future enhancements for the release of a second generation of devices.
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Affiliation(s)
- Annarita Cutrone
- The Biorobotics Institute, Viale Rinaldo Piaggio 34, 56025, Pontedera, Italy
| | - Silvestro Micera
- The Biorobotics Institute, Viale Rinaldo Piaggio 34, 56025, Pontedera, Italy
- Bertarelli Foundation Chair in Translational Neuroengineering, Centre for Neuroprosthetics and Institute of Bioengineering, School of Engineering, Ecole Polytechnique Federale de Lausanne (EPFL), Lausanne, CH-1202, Switzerland
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Khatoun A, Asamoah B, Mc Laughlin M. Investigating the Feasibility of Epicranial Cortical Stimulation Using Concentric-Ring Electrodes: A Novel Minimally Invasive Neuromodulation Method. Front Neurosci 2019; 13:773. [PMID: 31396045 PMCID: PMC6667561 DOI: 10.3389/fnins.2019.00773] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Accepted: 07/10/2019] [Indexed: 01/26/2023] Open
Abstract
BACKGROUND Invasive cortical stimulation (ICS) is a neuromodulation method in which electrodes are implanted on the cortex to deliver chronic stimulation. ICS has been used to treat neurological disorders such as neuropathic pain, epilepsy, movement disorders and tinnitus. Noninvasive neuromodulation methods such as transcranial magnetic stimulation and transcranial electrical stimulation (TES) show great promise in treating some neurological disorders and require no surgery. However, only acute stimulation can be delivered. Epicranial current stimulation (ECS) is a novel concept for delivering chronic neuromodulation through subcutaneous electrodes implanted on the skull. The use of concentric-ring ECS electrodes may allow spatially focused stimulation and offer a less invasive alternative to ICS. OBJECTIVES Demonstrate ECS proof-of-concept using concentric-ring electrodes in rats and then use a computational model to explore the feasibility and limitations of ECS in humans. METHODS ECS concentric-ring electrodes were implanted in 6 rats and pulsatile stimulation delivered to the motor cortex. An MRI based electro-anatomical human head model was used to explore different ECS concentric-ring electrode designs and these were compared with ICS and TES. RESULTS Concentric-ring ECS electrodes can selectively stimulate the rat motor cortex. The computational model showed that the concentric-ring ECS electrode design can be optimized to achieve focused cortical stimulation. In general, focality was less than ICS but greater than noninvasive transcranial current stimulation. CONCLUSION ECS could be a promising minimally invasive alternative to ICS. Further work in large animal models and patients is needed to demonstrate feasibility and long-term stability.
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Affiliation(s)
- Ahmad Khatoun
- Research Group Experimental Oto-Rhino-Laryngology (ExpORL), Department of Neurosciences, KU Leuven, Leuven, Belgium
- The Leuven Brain Institute, KU Leuven, Leuven, Belgium
| | - Boateng Asamoah
- Research Group Experimental Oto-Rhino-Laryngology (ExpORL), Department of Neurosciences, KU Leuven, Leuven, Belgium
- The Leuven Brain Institute, KU Leuven, Leuven, Belgium
| | - Myles Mc Laughlin
- Research Group Experimental Oto-Rhino-Laryngology (ExpORL), Department of Neurosciences, KU Leuven, Leuven, Belgium
- The Leuven Brain Institute, KU Leuven, Leuven, Belgium
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Bax DV, Yin Y, Kondyurin A, Diwan AD, Bhargav D, Weiss AS, Bilek MMM, McKenzie DR. Plasma processing of PDMS based spinal implants for covalent protein immobilization, cell attachment and spreading. JOURNAL OF MATERIALS SCIENCE. MATERIALS IN MEDICINE 2018; 29:178. [PMID: 30506173 DOI: 10.1007/s10856-018-6181-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Accepted: 10/19/2018] [Indexed: 06/09/2023]
Abstract
PDMS is widely used for prosthetic device manufacture. Conventional ion implantation is not a suitable treatment to enhance the biocompatibility of poly dimethyl siloxane (PDMS) due to its propensity to generate a brittle silicon oxide surface layer which cracks and delaminates. To overcome this limitation, we have developed new plasma based processes to balance the etching of carbon with implantation of carbon from the plasma source. When this carbon was implanted from the plasma phase it resulted in a surface that was structurally similar and intermixed with the underlying PDMS material and not susceptible to delamination. The enrichment in surface carbon allowed the formation of carbon based radicals that are not present in conventional plasma ion immersion implantation (PIII) treated PDMS. This imparts the PDMS surfaces with covalent protein binding capacity that is not observed on PIII treated PDMS. The change in surface energy preserved the function of bound biomolecules and enhanced the attachment of MG63 osteosarcoma cells compared to the native surface. The attached cells, an osteoblast interaction model, showed increased spreading on the treated over untreated surfaces. The carbon-dependency for these beneficial covalent protein and cell linkage properties was tested by incorporating carbon from a different source. To this end, a second surface was produced where carbon etching was balanced against implantation from a thin carbon-based polymer coating. This had similar protein and cell-binding properties to the surfaces generated with carbon inclusion in the plasma phase, thus highlighting the importance of balancing carbon etching and deposition. Additionally, the two effects of protein linkage and bioactivity could be combined where the cell response was further enhanced by covalently tethering a biomolecule coating, as exemplified here with the cell adhesive protein tropoelastin. Providing a balanced carbon source in the plasma phase is applicable to prosthetic device fabrication as illustrated using a 3-dimensional PDMS balloon prosthesis for spinal implant applications. Consequently, this study lays the groundwork for effective treatments of PDMS to selectively recruit cells to implantable PDMS fabricated biodevices.
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Affiliation(s)
- Daniel V Bax
- School of Physics, University of Sydney, Sydney, NSW, 2006, Australia.
- Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge, CB3 0FS, UK.
| | - Yongbai Yin
- School of Physics, University of Sydney, Sydney, NSW, 2006, Australia
| | - Alexey Kondyurin
- School of Physics, University of Sydney, Sydney, NSW, 2006, Australia
| | - Ashish D Diwan
- Spine Service, St George and Sutherland Clinical School, University of New South Wales, Sydney, NSW, 2217, Australia
| | - Divya Bhargav
- Spine Service, St George and Sutherland Clinical School, University of New South Wales, Sydney, NSW, 2217, Australia
| | - Anthony S Weiss
- Life and Environmental Sciences, University of Sydney, Sydney, NSW, 2006, Australia
- Charles Perkins Centre, University of Sydney, Sydney, NSW, 2006, Australia
- Bosch Institute, University of Sydney, Sydney, NSW, 2006, Australia
| | - Marcela M M Bilek
- School of Physics, University of Sydney, Sydney, NSW, 2006, Australia
| | - David R McKenzie
- School of Physics, University of Sydney, Sydney, NSW, 2006, Australia
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Simple and fast polydimethylsiloxane (PDMS) patterning using a cutting plotter and vinyl adhesives to achieve etching results. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2018; 2017:1885-1888. [PMID: 29060259 DOI: 10.1109/embc.2017.8037215] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Inhibition of polydimethylsiloxane (PDMS) polymerization could be observed when spin-coated over vinyl substrates. The degree of polymerization, partially curing or fully curing, depended on the PDMS thickness coated over the vinyl substrate. This characteristic was exploited to achieve simple and fast PDMS patterning method using a vinyl adhesive layer patterned through a cutting plotter. The proposed patterning method showed results resembling PDMS etching. Therefore, patterning PDMS over PDMS, glass, silicon, and gold substrates were tested to compare the results with conventional etching methods. Vinyl stencils with widths ranging from 200μm to 1500μm were used for the procedure. To evaluate the accuracy of the cutting plotter, stencil designed on the AutoCAD software and the actual stencil widths were compared. Furthermore, this method's accuracy was also evaluated by comparing the widths of the actual stencils and etched PDMS results.
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12
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Tan EKW, Rughoobur G, Rubio-Lara J, Tiwale N, Xiao Z, Davidson CAB, Lowe CR, Occhipinti LG. Nanofabrication of Conductive Metallic Structures on Elastomeric Materials. Sci Rep 2018; 8:6607. [PMID: 29700337 PMCID: PMC5920093 DOI: 10.1038/s41598-018-24901-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Accepted: 04/09/2018] [Indexed: 11/09/2022] Open
Abstract
Existing techniques for patterning metallic structures on elastomers are limited in terms of resolution, yield and scalability. The primary constraint is the incompatibility of their physical properties with conventional cleanroom techniques. We demonstrate a reliable fabrication strategy to transfer high resolution metallic structures of <500 nm in dimension on elastomers. The proposed method consists of producing a metallic pattern using conventional lithographic techniques on silicon coated with a thin sacrificial aluminium layer. Subsequent wet etching of the sacrificial layer releases the elastomer with the embedded metallic pattern. Using this method, a nano-resistor with minimum feature size of 400 nm is fabricated on polydimethylsiloxane (PDMS) and applied in gas sensing. Adsorption of solvents in the PDMS causes swelling and increases the device resistance, which therefore enables the detection of volatile organic compounds (VOCs). Sensitivity to chloroform and toluene vapor with a rapid response (~30 s) and recovery (~200 s) is demonstrated using this PDMS nano-resistor at room temperature.
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Affiliation(s)
- Edward K W Tan
- Department of Engineering, University of Cambridge, Cambridge, CB3 0FA, UK.
| | - Girish Rughoobur
- Department of Engineering, University of Cambridge, Cambridge, CB3 0FA, UK.,Microsystems Technology Laboratories, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Juan Rubio-Lara
- Nanoscience Centre, University of Cambridge, Cambridge, CB3 0FF, UK
| | - Nikhil Tiwale
- Nanoscience Centre, University of Cambridge, Cambridge, CB3 0FF, UK
| | - Zhuocong Xiao
- Nanoscience Centre, University of Cambridge, Cambridge, CB3 0FF, UK
| | - Colin A B Davidson
- Institute of Biotechnology, University of Cambridge, Cambridge, CB2 1QT, UK
| | - Christopher R Lowe
- Institute of Biotechnology, University of Cambridge, Cambridge, CB2 1QT, UK
| | - Luigi G Occhipinti
- Department of Engineering, University of Cambridge, Cambridge, CB3 0FA, UK.
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13
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Savov A, Joshi S, Shafqat S, Hoefnagels J, Louwerse M, Stoute R, Dekker R. A Platform for Mechano(-Electrical) Characterization of Free-Standing Micron-Sized Structures and Interconnects. MICROMACHINES 2018; 9:E39. [PMID: 30393314 PMCID: PMC6187293 DOI: 10.3390/mi9010039] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Revised: 01/10/2018] [Accepted: 01/12/2018] [Indexed: 11/16/2022]
Abstract
A device for studying the mechanical and electrical behavior of free-standing micro-fabricated metal structures, subjected to a very large deformation, is presented in this paper. The free-standing structures are intended to serve as interconnects in high-density, highly stretchable electronic circuits. For an easy, damage-free handling and mounting of these free-standing structures, the device is designed to be fabricated as a single chip/unit that is separated into two independently movable parts after it is fixed in the tensile test stage. Furthermore, the fabrication method allows for test structures of different geometries to be easily fabricated on the same substrate. The utility of the device has been demonstrated by stretching the free-standing interconnect structures in excess of 1000% while simultaneously measuring their electrical resistance. Important design considerations and encountered processing challenges and their solutions are discussed in this paper.
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Affiliation(s)
- Angel Savov
- Department of Microelectronics, Delft University of Technology, 2628 CD Delft, The Netherlands.
| | - Shivani Joshi
- Department of Microelectronics, Delft University of Technology, 2628 CD Delft, The Netherlands.
| | - Salman Shafqat
- Department of Mechanical Engineering, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands.
| | - Johan Hoefnagels
- Department of Mechanical Engineering, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands.
| | - Marcus Louwerse
- Philips Research, High Tech Campus 4, 5654 AE Eindhoven, The Netherlands.
| | - Ronald Stoute
- Department of Microelectronics, Delft University of Technology, 2628 CD Delft, The Netherlands.
| | - Ronald Dekker
- Department of Microelectronics, Delft University of Technology, 2628 CD Delft, The Netherlands.
- Philips Research, High Tech Campus 4, 5654 AE Eindhoven, The Netherlands.
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14
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Plateau-Shaped Flexible Polymer Microelectrode Array for Neural Recording. Polymers (Basel) 2017; 9:polym9120690. [PMID: 30965988 PMCID: PMC6418796 DOI: 10.3390/polym9120690] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Revised: 12/04/2017] [Accepted: 12/05/2017] [Indexed: 11/30/2022] Open
Abstract
Conventional polymer multielectrode arrays (MEAs) have limitations resulting from a high Young’s modulus, including low conformability and gaps between the electrodes and neurons. These gaps are not a problem in soft tissues such as the brain, due to the repopulation phenomenon. However, gaps can result in signal degradation when recording from a fiber bundle, such as the spinal cord. Methods: We propose a method for fabricating flexible polydimethylsiloxane (PDMS)-based MEAs featuring plateau-shaped microelectrodes. The proposed fabrication technique enables the electrodes on the surface of MEAs to make a tight connection to the neurons, because the wire of the MEA is fabricated to be plateau-shaped, as the Young’s modulus of PDMS is similar to soft tissues and PDMS follows the curvature of the neural tissue due to its high conformability compared to the other polymers. Injury caused by the movement of the MEAs can therefore be minimized. Each electrode has a diameter of 130 μm and the 8-channel array has a center-to-center electrode spacing of 300 μm. The signal-to-noise ratio of the plateau-shaped electrodes was larger than that of recessed electrodes because there was no space between the electrode and neural cell. Reliable neural recordings were possible by adjusting the position of the electrode during the experiment without trapping air under the electrodes. Simultaneous multi-channel neural recordings were successfully achieved from the spinal cord of rodents. We describe the fabrication technique, electrode 3D profile, electrode impedance, and MEA performance in in vivo experiments in rodents.
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15
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Guvanasen GS, Guo L, Aguilar RJ, Cheek AL, Shafor CS, Rajaraman S, Nichols TR, DeWeerth SP. A Stretchable Microneedle Electrode Array for Stimulating and Measuring Intramuscular Electromyographic Activity. IEEE Trans Neural Syst Rehabil Eng 2017; 25:1440-1452. [DOI: 10.1109/tnsre.2016.2629461] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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16
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Hill S, Qian W, Chen W, Fu J. Surface micromachining of polydimethylsiloxane for microfluidics applications. BIOMICROFLUIDICS 2016; 10:054114. [PMID: 27795746 PMCID: PMC5065565 DOI: 10.1063/1.4964717] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Accepted: 09/29/2016] [Indexed: 06/06/2023]
Abstract
Polydimethylsiloxane (PDMS) elastomer has emerged as one of the most frequently applied materials in microfluidics. However, precise and large-scale surface micromachining of PDMS remains challenging, limiting applications of PDMS for microfluidic structures with high-resolution features. Herein, surface patterning of PDMS was achieved using a simple yet effective method combining direct photolithography followed by reactive-ion etching (RIE). This method incorporated a unique step of using oxygen plasma to activate PDMS surfaces to a hydrophilic state, thereby enabling improved adhesion of photoresist on top of PDMS surfaces for subsequent photolithography. RIE was applied to transfer patterns from photoresist to underlying PDMS thin films. Systematic experiments were conducted in the present work to characterize PDMS etch rate and etch selectivity of PDMS to photoresist as a function of various RIE parameters, including pressure, RF power, and gas flow rate and composition. We further compared two common RIE systems with and without bias power and employed inductively coupled plasma and capacitively coupled plasma sources, respectively, in terms of their PDMS etching performances. The RIE-based PDMS surface micromachining technique is compatible with conventional Si-based surface and bulk micromachining techniques, thus opening promising opportunities for generating hybrid microfluidic devices with novel functionalities.
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Affiliation(s)
| | - Weiyi Qian
- Department of Mechanical and Aerospace Engineering, New York University , Brooklyn, New York 11201, USA
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17
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Kazimierczak B, Pijanowska D, Baraniecka A, Dawgul M, Kruk J, Torbicz W. Immunosensors for human cardiac troponins and CRP, in particular amperometric cTnI immunosensor. Biocybern Biomed Eng 2016. [DOI: 10.1016/j.bbe.2015.11.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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18
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Scholten K, Meng E. Materials for microfabricated implantable devices: a review. LAB ON A CHIP 2015; 15:4256-72. [PMID: 26400550 DOI: 10.1039/c5lc00809c] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
The application of microfabrication to the development of biomedical implants has produced a new generation of miniaturized technology for assisting treatment and research. Microfabricated implantable devices (μID) are an increasingly important tool, and the development of new μIDs is a rapidly growing field that requires new microtechnologies able to safely and accurately function in vivo. Here, we present a review of μID research that examines the critical role of material choice in design and fabrication. Materials commonly used for μID production are identified and presented along with their relevant physical properties and a survey of the state-of-the-art in μID development. The consequence of material choice as it pertains to microfabrication and biocompatibility is discussed in detail with a particular focus on the divide between hard, rigid materials and soft, pliable polymers.
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Affiliation(s)
- Kee Scholten
- Department of Biomedical Engineering, Univ. of Southern California, Los Angeles, CA 90089-1111, USA.
| | - Ellis Meng
- Department of Biomedical Engineering, Univ. of Southern California, Los Angeles, CA 90089-1111, USA.
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19
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Zhu G, Li X, Pu J, Chen W, Luo Q. Transient alterations in slow oscillations of hippocampal networks by low-frequency stimulations on multi-electrode arrays. Biomed Microdevices 2015; 12:153-8. [PMID: 19937128 DOI: 10.1007/s10544-009-9370-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Slow oscillations in the hippocampus are correlated with memory consolidation and brain diseases. The characteristic firings of the hippocampal network in vitro are still poorly understood. Here, spontaneous oscillations(~0.004 Hz) were found in high-density hippocampal networks by multi-electrode arrays after 30 days in vitro.This kind of spontaneous activity was characterized by periodic synchronized superbursts, which persisted for approximately 60 s at long intervals. Additionally, 1-Hz stimulation (duration <120 s) could regulate these network wide oscillatory activities by triggering the next synchronized superbursts prematurely. The results demonstrated that the slow oscillatory activities in hippocampal cultures could be regulated by external stimulation, which indicates that multi-electrode arrays provide a well-suited platform for studying the dynamics of slow oscillations in vitro and may help to elucidate the mechanism of electrical stimulation therapy.
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Affiliation(s)
- Geng Zhu
- Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430074 Huber, China
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20
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Fattahi P, Yang G, Kim G, Abidian MR. A review of organic and inorganic biomaterials for neural interfaces. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2014; 26:1846-85. [PMID: 24677434 PMCID: PMC4373558 DOI: 10.1002/adma.201304496] [Citation(s) in RCA: 300] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2013] [Revised: 10/08/2013] [Indexed: 05/18/2023]
Abstract
Recent advances in nanotechnology have generated wide interest in applying nanomaterials for neural prostheses. An ideal neural interface should create seamless integration into the nervous system and performs reliably for long periods of time. As a result, many nanoscale materials not originally developed for neural interfaces become attractive candidates to detect neural signals and stimulate neurons. In this comprehensive review, an overview of state-of-the-art microelectrode technologies provided fi rst, with focus on the material properties of these microdevices. The advancements in electro active nanomaterials are then reviewed, including conducting polymers, carbon nanotubes, graphene, silicon nanowires, and hybrid organic-inorganic nanomaterials, for neural recording, stimulation, and growth. Finally, technical and scientific challenges are discussed regarding biocompatibility, mechanical mismatch, and electrical properties faced by these nanomaterials for the development of long-lasting functional neural interfaces.
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Affiliation(s)
- Pouria Fattahi
- Biomedical Engineering Department and Chemical Engineering Departments, Pennsylvania State University, University Park, PA, 16802, USA
| | - Guang Yang
- Biomedical Engineering Department, Pennsylvania State University, University Park, PA, 16802, USA
| | - Gloria Kim
- Biomedical Engineering Department, Pennsylvania State University, University Park, PA, 16802, USA
| | - Mohammad Reza Abidian
- Biomedical Engineering Department, Materials Science & Engineering Department, Chemical Engineering Department, Materials Research Institute, Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA, 16802, USA
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21
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Hammock ML, Chortos A, Tee BCK, Tok JBH, Bao Z. 25th anniversary article: The evolution of electronic skin (e-skin): a brief history, design considerations, and recent progress. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2013; 25:5997-6038. [PMID: 24151185 DOI: 10.1002/adma.201302240] [Citation(s) in RCA: 891] [Impact Index Per Article: 81.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Revised: 06/22/2013] [Indexed: 05/19/2023]
Abstract
Human skin is a remarkable organ. It consists of an integrated, stretchable network of sensors that relay information about tactile and thermal stimuli to the brain, allowing us to maneuver within our environment safely and effectively. Interest in large-area networks of electronic devices inspired by human skin is motivated by the promise of creating autonomous intelligent robots and biomimetic prosthetics, among other applications. The development of electronic networks comprised of flexible, stretchable, and robust devices that are compatible with large-area implementation and integrated with multiple functionalities is a testament to the progress in developing an electronic skin (e-skin) akin to human skin. E-skins are already capable of providing augmented performance over their organic counterpart, both in superior spatial resolution and thermal sensitivity. They could be further improved through the incorporation of additional functionalities (e.g., chemical and biological sensing) and desired properties (e.g., biodegradability and self-powering). Continued rapid progress in this area is promising for the development of a fully integrated e-skin in the near future.
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Affiliation(s)
- Mallory L Hammock
- Department of Chemical Engineering, 381 N. South Axis, Stanford University, Stanford, CA, 94305, USA
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22
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Inam Ul Ahad, Bartnik A, Fiedorowicz H, Kostecki J, Korczyc B, Ciach T, Brabazon D. Surface modification of polymers for biocompatibility via exposure to extreme ultraviolet radiation. J Biomed Mater Res A 2013; 102:3298-310. [PMID: 24132935 DOI: 10.1002/jbm.a.34958] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2013] [Revised: 07/16/2013] [Accepted: 09/09/2013] [Indexed: 01/02/2023]
Abstract
Polymeric biomaterials are being widely used for the treatment of various traumata, diseases and defects in human beings due to ease in their synthesis. As biomaterials have direct interaction with the extracellular environment in the biological world, biocompatibility is a topic of great significance. The introduction or enhancement of biocompatibility in certain polymers is still a challenge to overcome. Polymer biocompatibility can be controlled by surface modification. Various physical and chemical methods (e.g., chemical and plasma treatment, ion implantation, and ultraviolet irradiation etc.) are in use or being developed for the modification of polymer surfaces. However an important limitation in their employment is the alteration of bulk material. Different surface and bulk properties of biomaterials are often desirable for biomedical applications. Because extreme ultraviolet (EUV) radiation penetration is quite limited even in low density mediums, it could be possible to use it for surface modification without influencing the bulk material. This article reviews the degree of biocompatibility of different polymeric biomaterials being currently employed in various biomedical applications, the surface properties required to be modified for biocompatibility control, plasma and laser ablation based surface modification techniques, and research studies indicating possible use of EUV for enhancing biocompatibility.
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Affiliation(s)
- Inam Ul Ahad
- Institute of Optoelectronics, Military University of Technology, 00-908, Warsaw, Poland; Advanced Processing Technology Research Centre, School of Mechanical and Manufacturing Engineering, Faculty of Engineering and Computing, Dublin City University, Dublin 9, Ireland
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23
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Kim JM, Oh DR, Sanchez J, Kim SH, Seo JM. Fabrication of polydimethylsiloxane (PDMS) - based multielectrode array for neural interface. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2013; 2013:1716-9. [PMID: 24110037 DOI: 10.1109/embc.2013.6609850] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Flexible multielectrode arrays (MEAs) are being developed with various materials, and polyimide has been widely used due to the conveniece of process. Polyimide is developed in the form of photoresist. And this enable precise and reproducible fabrication. PDMS is another good candidate for MEA base material, but it has poor surface energy and etching property. In this paper, we proposed a better fabrication process that could modify PDMS surface for a long time and open the site of electrode and pad efficiently without PDMS etching.
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24
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Khaled I, Elmallah S, Cheng C, Moussa WA, Mushahwar VK, Elias AL. A flexible base electrode array for intraspinal microstimulation. IEEE Trans Biomed Eng 2013; 60:2904-13. [PMID: 23744656 DOI: 10.1109/tbme.2013.2265877] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
In this paper, we report the development of a flexible base array of penetrating electrodes which can be used to interface with the spinal cord. A customizable and feasible fabrication protocol is described. The flexible base arrays were fabricated and implanted into surrogate cords which were elongated by 12%. The resulting strains were optically measured across the cord and compared to those associated with two types of electrodes arrays (one without a base and one with a rigid base connecting the electrodes). The deformation behavior of cords implanted with the flexible base arrays resembled the behavior of cords implanted with individual microwires that were not connected through a base. The results of the strain test were used to validate a 2-D finite element model. The validated model was used to assess the stresses induced by the electrodes of the three types of arrays on the cord, and to examine how various design parameters (thickness, base modulus, etc.,) impact the mechanical behavior of the electrode array. Rigid base arrays induced higher stresses on the cord than the flexible base arrays which in turn imposed higher stresses than the individual microwire implants. The developed flexible base array showed improvement over the rigid base array; however, its stiffness needs to be further reduced to emulate the mechanical behavior of individual microwire arrays without a base.
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25
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Guvanasen GS, Tuthill C, Nichols TR, DeWeerth SP. A PDMS-based integrated stretchable microelectrode array (isMEA) for neural and muscular surface interfacing. IEEE TRANSACTIONS ON BIOMEDICAL CIRCUITS AND SYSTEMS 2013; 7:1-10. [PMID: 23853274 DOI: 10.1109/tbcas.2012.2192932] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Numerous applications in neuroscience research and neural prosthetics, such as electrocorticogram (ECoG) recording and retinal prosthesis, involve electrical interactions with soft excitable tissues using a surface recording and/or stimulation approach. These applications require an interface that is capable of setting up high-throughput communications between the electrical circuit and the excitable tissue and that can dynamically conform to the shape of the soft tissue. Being a compliant material with mechanical impedance close to that of soft tissues, polydimethylsiloxane (PDMS) offers excellent potential as a substrate material for such neural interfaces. This paper describes an integrated technology for fabrication of PDMS-based stretchable microelectrode arrays (MEAs). Specifically, as an integral part of the fabrication process, a stretchable MEA is directly fabricated with a rigid substrate, such as a thin printed circuit board (PCB), through an innovative bonding technology-via-bonding-for integrated packaging. This integrated strategy overcomes the conventional challenge of high-density packaging for this type of stretchable electronics. Combined with a high-density interconnect technology developed previously, this stretchable MEA technology facilitates a high-resolution, high-density integrated system solution for neural and muscular surface interfacing. In this paper, this PDMS-based integrated stretchable MEA (isMEA) technology is demonstrated by an example design that packages a stretchable MEA with a small PCB. The resulting isMEA is assessed for its biocompatibility, surface conformability, electrode impedance spectrum, and capability to record muscle fiber activity when applied epimysially.
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26
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Delivopoulos E, Chew DJ, Minev IR, Fawcett JW, Lacour SP. Concurrent recordings of bladder afferents from multiple nerves using a microfabricated PDMS microchannel electrode array. LAB ON A CHIP 2012; 12:2540-2551. [PMID: 22569953 DOI: 10.1039/c2lc21277c] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
In this paper we present a compliant neural interface designed to record bladder afferent activity. We developed the implant's microfabrication process using multiple layers of silicone rubber and thin metal so that a gold microelectrode array is embedded within four parallel polydimethylsiloxane (PDMS) microchannels (5 mm long, 100 μm wide, 100 μm deep). Electrode impedance at 1 kHz was optimized using a reactive ion etching (RIE) step, which increased the porosity of the electrode surface. The electrodes did not deteriorate after a 3 month immersion in phosphate buffered saline (PBS) at 37 °C. Due to the unique microscopic topography of the metal film on PDMS, the electrodes are extremely compliant and can withstand handling during implantation (twisting and bending) without electrical failure. The device was transplanted acutely to anaesthetized rats, and strands of the dorsal branch of roots L6 and S1 were surgically teased and inserted in three microchannels under saline immersion to allow for simultaneous in vivo recordings in an acute setting. We utilized a tripole electrode configuration to maintain background noise low and improve the signal to noise ratio. The device could distinguish two types of afferent nerve activity related to increasing bladder filling and contraction. To our knowledge, this is the first report of multichannel recordings of bladder afferent activity.
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Graudejus O, Jia Z, Li T, Wagner S. Size-Dependent Rupture Strain of Elastically Stretchable Metal Conductors. SCRIPTA MATERIALIA 2012; 66:919-922. [PMID: 22773917 PMCID: PMC3388513 DOI: 10.1016/j.scriptamat.2012.02.034] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Experiments show that the rupture strain of gold conductors on elastomers decreases as the conductors are made long and narrow. Rupture is caused by the irreversible coalescence of microcracks into one long crack. A mechanics model identifies a critical crack length ℓ(cr), above which the long crack propagates across the entire conductor width. ℓ(cr) depends on the fracture toughness of the gold film and the width of the conductor. The model provides guidance for the design of highly stretchable conductors.
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Affiliation(s)
- O. Graudejus
- Department of Chemistry and Biochemistry, and Center for Adaptive Neural Systems, Arizona State University, Tempe, Arizona 85287
| | - Z. Jia
- Department of Mechanical Engineering, and Maryland NanoCenter, University of Maryland, College Park, Maryland 20742
| | - T. Li
- Department of Mechanical Engineering, and Maryland NanoCenter, University of Maryland, College Park, Maryland 20742
| | - S. Wagner
- Department of Electrical Engineering and Princeton Institute for the Science and Technology of Materials, Princeton University, Princeton, New Jersey 08544
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28
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Minev IR, Chew DJ, Delivopoulos E, Fawcett JW, Lacour SP. High sensitivity recording of afferent nerve activity using ultra-compliant microchannel electrodes: an acutein vivovalidation. J Neural Eng 2012; 9:026005. [DOI: 10.1088/1741-2560/9/2/026005] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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29
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Graudejus O, Morrison B, Goletiani C, Yu Z, Wagner S. Encapsulating Elastically Stretchable Neural Interfaces: Yield, Resolution, and Recording/Stimulation of Neural Activity. ADVANCED FUNCTIONAL MATERIALS 2012; 22:640-651. [PMID: 24093006 PMCID: PMC3788117 DOI: 10.1002/adfm.201102290] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
A high resolution elastically stretchable microelectrode array (SMEA) to interface with neural tissue is described. The SMEA consists of an elastomeric substrate, such as poly(dimethylsiloxane) (PDMS), elastically stretchable gold conductors, and an electrically insulating encapsulating layer in which contact holes are opened. We demonstrate the feasibility of producing contact holes with 40 µm × 40 µm openings, show why the adhesion of the encapsulation layer to the underlying silicone substrate is weakened during contact hole fabrication, and provide remedies. These improvements result in greatly increased fabrication yield and reproducibility. An SMEA with 28 microelectrodes was fabricated. The contact holes (100 µm × 100 µm) in the encapsulation layer are only ~10% the size of the previous generation, allowing a larger number of microelectrodes per unit area, thus affording the capability to interface with a smaller neural population per electrode. This new SMEA is used to record spontaneous and evoked activity in organotypic hippocampal tissue slices at 0% strain before stretching, at 5 % and 10 % equibiaxial strain, and again at 0% strain after relaxation. The noise of the recordings increases with increasing strain. The frequency of spontaneous neural activity also increases when the SMEA is stretched. Upon relaxation, the noise returns to pre-stretch levels, while the frequency of neural activity remains elevated. Stimulus-response curves at each strain level are measured. The SMEA shows excellent biocompatibility for at least two weeks.
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Affiliation(s)
- Oliver Graudejus
- Department of Chemistry and Biochemistry and Center for Adaptive Neural Systems, Arizona State University, Tempe, Arizona 85287 (USA),
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30
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Chen W, Lam RHW, Fu J. Photolithographic surface micromachining of polydimethylsiloxane (PDMS). LAB ON A CHIP 2012; 12:391-5. [PMID: 22089984 PMCID: PMC4120064 DOI: 10.1039/c1lc20721k] [Citation(s) in RCA: 77] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
A major technical hurdle in microfluidics is the difficulty in achieving high fidelity lithographic patterning on polydimethylsiloxane (PDMS). Here, we report a simple yet highly precise and repeatable PDMS surface micromachining method using direct photolithography followed by reactive ion etching (RIE). Our method to achieve surface patterning of PDMS applied an O(2) plasma treatment to PDMS to activate its surface to overcome the challenge of poor photoresist adhesion on PDMS for photolithography. Our photolithographic PDMS surface micromachining technique is compatible with conventional soft lithography techniques and other silicon-based surface and bulk micromachining methods. To illustrate the general application of our method, we demonstrated fabrication of large microfiltration membranes and free-standing beam structures in PDMS.
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Affiliation(s)
- Weiqiang Chen
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan, 48109, USA
| | - Raymond H. W. Lam
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan, 48109, USA
- Department of Mechanical and Biomedical Engineering, City University of Hong Kong, Kowloon, Hong Kong, China
| | - Jianping Fu
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan, 48109, USA
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan, 48109, USA
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31
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Khodagholy D, Doublet T, Gurfinkel M, Quilichini P, Ismailova E, Leleux P, Herve T, Sanaur S, Bernard C, Malliaras GG. Highly conformable conducting polymer electrodes for in vivo recordings. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2011; 23:H268-72. [PMID: 21826747 DOI: 10.1002/adma.201102378] [Citation(s) in RCA: 204] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2011] [Indexed: 05/20/2023]
Affiliation(s)
- Dion Khodagholy
- Department of Bioelectronics, Centre Microélectronique de Provence, Ecole Nationale Supérieure des Mines de Saint Etienne, Gardanne, France
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32
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Diebold RM, Clarke DR. Lithographic patterning on polydimethylsiloxane surfaces using polydimethylglutarimide. LAB ON A CHIP 2011; 11:1694-1697. [PMID: 21445413 DOI: 10.1039/c0lc00732c] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We present a method for high fidelity lithographic patterning on polydimethylsiloxane (PDMS) surfaces employing traditional cleanroom equipment and commercially available materials that overcomes previous problems in PDMS processing. To illustrate this method, an electrostatically actuated microfluidic pump and rectangular diffraction gratings were fabricated on PDMS.
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Affiliation(s)
- Roger M Diebold
- School of Engineering and Applied Sciences, Harvard University, 29 Oxford St, Cambridge, MA 02138, USA.
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33
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Nandra MS, Lavrov IA, Edgerton VR, Tai YC. A PARYLENE-BASED MICROELECTRODE ARRAY IMPLANT FOR SPINAL CORD STIMULATION IN RATS. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2011; 2011:1007-1010. [PMID: 21841938 PMCID: PMC3154740 DOI: 10.1109/memsys.2011.5734598] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The design and fabrication of an epidural spinal cord implant using a parylene-based microelectrode array is presented. Rats with hindlimb paralysis from a complete spinal cord transection were implanted with the device and studied for up to eight weeks, where we have demonstrated recovery of hindlimb stepping functionality through pulsed stimulation. The microelectrode array allows for a high degree of freedom and specificity in selecting the site of stimulation compared to wire-based implants, and triggers varied biological responses that can lead to an increased understanding of the spinal cord and locomotion recovery for victims of spinal cord injury.
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34
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McClain MA, Clements IP, Shafer RH, Bellamkonda RV, LaPlaca MC, Allen MG. Highly-compliant, microcable neuroelectrodes fabricated from thin-film gold and PDMS. Biomed Microdevices 2011; 13:361-73. [DOI: 10.1007/s10544-010-9505-3] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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35
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Guo L, DeWeerth SP. An effective lift-off method for patterning high-density gold interconnects on an elastomeric substrate. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2010; 6:2847-52. [PMID: 21104803 PMCID: PMC3272486 DOI: 10.1002/smll.201001456] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
High-resolution, high-density gold interconnects are effectively patterned on an elastomeric substrate. A 3cm cable of ten gold wires with 10μm width and 20μm pitch is achieved, successfully demonstrating density increases of more than one order of magnitude from previously established work. Many applications in the fields of stretchable electronics and conformable neural interfaces will benefit from these fabrication developments.
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36
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Yu Z, Graudejus O, Tsay C, Lacour SP, Wagner S, Morrison B. Monitoring hippocampus electrical activity in vitro on an elastically deformable microelectrode array. J Neurotrauma 2010; 26:1135-45. [PMID: 19594385 DOI: 10.1089/neu.2008.0810] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Interfacing electronics and recording electrophysiological activity in mechanically active biological tissues is challenging. This challenge extends to recording neural function of brain tissue in the setting of traumatic brain injury (TBI), which is caused by rapid (within hundreds of milliseconds) and large (greater than 5% strain) brain deformation. Interfacing electrodes must be biocompatible on multiple levels and should deform with the tissue to prevent additional mechanical damage. We describe an elastically stretchable microelectrode array (SMEA) that is capable of undergoing large, biaxial, 2-D stretch while remaining functional. The new SMEA consists of elastically stretchable thin metal films on a silicone membrane. It can stimulate and detect electrical activity from cultured brain tissue (hippocampal slices), before, during, and after large biaxial deformation. We have incorporated the SMEA into a well-characterized in vitro TBI research platform, which reproduces the biomechanics of TBI by stretching the SMEA and the adherent brain slice culture. Mechanical injury parameters, such as strain and strain rate, can be precisely controlled to generate specific levels of damage. The SMEA allowed for quantification of neuronal function both before and after injury, without breaking culture sterility or repositioning the electrodes for the injury event, thus enabling serial and long-term measurements. We report tests of the SMEA and an initial application to study the effect of mechanical stimuli on neuron function, which could be employed as a high-content, drug-screening platform for TBI.
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Affiliation(s)
- Zhe Yu
- Department of Biomedical Engineering, Columbia University, New York, New York 10027, USA
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37
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Graudejus O, Görrn P, Wagner S. Controlling the morphology of gold films on poly(dimethylsiloxane). ACS APPLIED MATERIALS & INTERFACES 2010; 2:1927-1933. [PMID: 20608644 DOI: 10.1021/am1002537] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Gold films on poly(dimethylsiloxane) (PDMS) have applications in stretchable electronics, tunable diffraction gratings, soft lithography and as neural interfaces. The electrical and optical properties of these films depend critically on the morphology of the gold. Therefore, we examine qualitatively and quantitatively the factors that affect the morphology of the gold film. Three morphologies can be produced controllably: microcracked, buckled, and smooth. Which morphology a gold film will adopt depends on the film stress and the growth mode of the film. The factors that affect the film stress and growth mode, and thus the morphology, are as follows: deposition temperature, film thickness, elastic modulus, adhesion layer thickness, surface properties of the PDMS, and mechanical prestrain applied during deposition. We discuss how the different components of the film stress and growth mode of the film affect the morphology.
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Affiliation(s)
- Oliver Graudejus
- Department of Electrical Engineering and Princeton Institute for the Science and Technology of Materials (PRISM), Princeton University, Princeton, New Jersey 08544, USA.
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38
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Guo L, Meacham KW, Hochman S, DeWeerth SP. A PDMS-based conical-well microelectrode array for surface stimulation and recording of neural tissues. IEEE Trans Biomed Eng 2010; 57:2485-94. [PMID: 20550983 DOI: 10.1109/tbme.2010.2052617] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
A method for fabricating polydimethylsiloxane (PDMS) based microelectrode arrays (MEAs) featuring novel conical-well microelectrodes is described. The fabrication technique is reliable and efficient, and facilitates controllability over both the depth and the slope of the conical wells. Because of the high-PDMS elasticity (as compared to other MEA substrate materials), this type of compliant MEA is promising for acute and chronic implantation in applications that benefit from conformable device contact with biological tissue surfaces and from minimal tissue damage. The primary advantage of the conical-well microelectrodes--when compared to planar electrodes--is that they provide an improved contact on tissue surface, which potentially provides isolation of the electrode microenvironment for better electrical interfacing. The raised wells increase the uniformity of current density distributions at both the electrode and tissue surfaces, and they also protect the electrode material from mechanical damage (e.g., from rubbing against the tissue). Using this technique, electrodes have been fabricated with diameters as small as 10 μm and arrays have been fabricated with center-to-center electrode spacings of 60 μm. Experimental results are presented, describing electrode-profile characterization, electrode-impedance measurement, and MEA-performance evaluation on fiber bundle recruitment in spinal cord white matter.
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Affiliation(s)
- Liang Guo
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA.
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39
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Flexible and stretchable micro-electrodes for in vitro and in vivo neural interfaces. Med Biol Eng Comput 2010; 48:945-54. [DOI: 10.1007/s11517-010-0644-8] [Citation(s) in RCA: 151] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2010] [Accepted: 05/27/2010] [Indexed: 10/19/2022]
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40
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Kim DH, Viventi J, Amsden JJ, Xiao J, Vigeland L, Kim YS, Blanco JA, Panilaitis B, Frechette ES, Contreras D, Kaplan DL, Omenetto FG, Huang Y, Hwang KC, Zakin MR, Litt B, Rogers JA. Dissolvable films of silk fibroin for ultrathin conformal bio-integrated electronics. NATURE MATERIALS 2010; 9:511-7. [PMID: 20400953 PMCID: PMC3034223 DOI: 10.1038/nmat2745] [Citation(s) in RCA: 794] [Impact Index Per Article: 56.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2009] [Accepted: 03/10/2010] [Indexed: 05/17/2023]
Abstract
Electronics that are capable of intimate, non-invasive integration with the soft, curvilinear surfaces of biological tissues offer important opportunities for diagnosing and treating disease and for improving brain/machine interfaces. This article describes a material strategy for a type of bio-interfaced system that relies on ultrathin electronics supported by bioresorbable substrates of silk fibroin. Mounting such devices on tissue and then allowing the silk to dissolve and resorb initiates a spontaneous, conformal wrapping process driven by capillary forces at the biotic/abiotic interface. Specialized mesh designs and ultrathin forms for the electronics ensure minimal stresses on the tissue and highly conformal coverage, even for complex curvilinear surfaces, as confirmed by experimental and theoretical studies. In vivo, neural mapping experiments on feline animal models illustrate one mode of use for this class of technology. These concepts provide new capabilities for implantable and surgical devices.
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Affiliation(s)
- Dae-Hyeong Kim
- Department of Materials Science and Engineering, Beckman Institute for Advanced Science and Technology and Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 USA
| | - Jonathan Viventi
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104 USA
| | - Jason J. Amsden
- Department of Biomedical Engineering, Tufts University, Medford, MA 02155, USA
| | - Jianliang Xiao
- Department of Mechanical Engineering and Department of Civil and Environmental Engineering, Northwestern University, Evanston, IL 60208
| | - Leif Vigeland
- Department of Neuroscience, University of Pennsylvania School of Medicine, 215 Stemmler Hall, Philadelphia, PA 19104 USA
| | - Yun-Soung Kim
- Department of Materials Science and Engineering, Beckman Institute for Advanced Science and Technology and Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 USA
| | - Justin A. Blanco
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104 USA
| | - Bruce Panilaitis
- Department of Biomedical Engineering, Tufts University, Medford, MA 02155, USA
| | - Eric S. Frechette
- Department of Neurology, Hospital of the University of Pennsylvania, 3 West Gates, 3400 Spruce Street, Philadelphia, PA 19104 USA
| | - Diego Contreras
- Department of Neuroscience, University of Pennsylvania School of Medicine, 215 Stemmler Hall, Philadelphia, PA 19104 USA
| | - David L. Kaplan
- Department of Biomedical Engineering, Tufts University, Medford, MA 02155, USA
| | | | - Yonggang Huang
- Department of Mechanical Engineering and Department of Civil and Environmental Engineering, Northwestern University, Evanston, IL 60208
| | - Keh-Chih Hwang
- AML, Department of Engineering Mechanics, Tsinghua University, Beijing 100084, China
| | | | - Brian Litt
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104 USA
- Department of Neurology, Hospital of the University of Pennsylvania, 3 West Gates, 3400 Spruce Street, Philadelphia, PA 19104 USA
- To whom correspondence should be addressed. ;
| | - John A. Rogers
- Department of Materials Science and Engineering, Beckman Institute for Advanced Science and Technology and Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 USA
- To whom correspondence should be addressed. ;
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41
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Yu Z, Graudejus O, Lacour SP, Wagner S, Morrison B. Neural sensing of electrical activity with stretchable microelectrode arrays. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2010; 2009:4210-3. [PMID: 19964344 DOI: 10.1109/iembs.2009.5333791] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Sensing neural activity within mechanically active tissues poses particular hurdles because most electrodes are much stiffer than biological tissues. As the tissue deforms, the rigid electrodes may damage the surrounding tissue. The problem is exacerbated when sensing neural activity in experimental models of traumatic brain injury (TBI) which is caused by the rapid and large deformation of brain tissue. We have developed a stretchable microelectrode array (SMEA) that can withstand large elastic deformations (>5% biaxial strain) while continuing to function. The SMEA were fabricated from thin metal conductors patterned on polydimethylsiloxane (PDMS) and encapsulated with a photo-patternable silicone. SMEA were used to record spontaneous activity from brain slice cultures, as well as evoked activity after stimulating through SMEA electrodes. Slices of brain tissue were grown on SMEA in long-term culture and then mechanically injured with our well-characterized in vitro injury model by stretching the SMEA and the adherent culture, which was confirmed by image analysis. Because brain tissue was grown on the substrate-integrated SMEA, post-injury changes in electrophysiological function were normalized to pre-injury function since the SMEA deformed with the tissue and remained in place during mechanical stimulation. The combination of our injury model and SMEA could help elucidate mechanisms responsible for post-traumatic neuronal dysfunction in the quest for TBI therapies. The SMEA may have additional sensing applications in other mechanically active tissues such as peripheral nerve and heart.
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Affiliation(s)
- Zhe Yu
- Biomedical Engineering Department, Columbia University, USA.
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42
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Guo L, Deweerth SP. PDMS-based conformable microelectrode arrays with selectable novel 3-D microelectrode geometries for surface stimulation and recording. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2010; 2009:1623-6. [PMID: 19964009 DOI: 10.1109/iembs.2009.5333446] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
A method for fabricating polydimethylsiloxane (PDMS) based conformable microelectrode arrays (MEAs) with selectable novel 3-D microelectrode geometries is presented. Simply recessed, conically recessed, exponentially recessed, and protruded-well microelectrodes have been fabricated on the MEA with a diameter as small as 10microm. 3-D microelectrode geometry parameters (recess depth, recess slope & profile, and protrusion/planar) can be controlled independently during fabrication. Exponentially and conically recessed microelectrodes are promising in chronic stimulation applications, such as neural prostheses, for their production of a uniform current density profile during stimulation, which can minimize stimulation-induced tissue burning and electrode corrosion. Protruded-well microelectrodes potentially provide a closer and sealed contact to the target tissue surface, avoiding current leakage during stimulation and thus achieving better stimulation efficiency in both charge delivery and spatial specificity.
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Affiliation(s)
- Liang Guo
- Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA 30332 USA.
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43
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Hao Z, Chen H, Ma D. Preparation of Micro Gold Devices on Poly(dimethylsiloxane) Chips with Region-Selective Electroless Plating. Anal Chem 2009; 81:8649-53. [DOI: 10.1021/ac901539n] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Zhenxia Hao
- Institute of Microanalytical Systems, Department of Chemistry, Zijin’gang Campus, Zhejiang University, Hangzhou 310058, China
| | - Hengwu Chen
- Institute of Microanalytical Systems, Department of Chemistry, Zijin’gang Campus, Zhejiang University, Hangzhou 310058, China
| | - Dan Ma
- Institute of Microanalytical Systems, Department of Chemistry, Zijin’gang Campus, Zhejiang University, Hangzhou 310058, China
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44
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Chien HW, Chang TY, Tsai WB. Spatial control of cellular adhesion using photo-crosslinked micropatterned polyelectrolyte multilayer films. Biomaterials 2009; 30:2209-18. [DOI: 10.1016/j.biomaterials.2008.12.060] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2008] [Accepted: 12/26/2008] [Indexed: 02/06/2023]
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45
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Guo L, Deweerth SP. Implementation of integratable PDMS-based conformable microelectrode arrays using a multilayer wiring interconnect technology. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2009; 2009:1619-1622. [PMID: 19964008 DOI: 10.1109/iembs.2009.5333218] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
To meet the emerging demand of high-throughput intimate interfaces in neuroscience research and neural prosthetics, a multilayer wiring interconnect technology for implementing high-density, integratable polydimethylsiloxane (PDMS) based conformable microelectrode arrays (MEAs) is developed. This technology has two parts: first, multilayer interconnects are fabricated within PDMS, which provides the potential for implementing high-density, large-capacity PDMS-based MEAs; second, interconnects are fabricated between PDMS and a substrate material, e.g., glass or silicon, which provides the potential for directly integrating PDMS-based MEAs with silicon-based ICs to achieve an integrated system solution for neural interfacing. Preliminary muscle surface recording experiments using a connector-integrated MEA have successfully demonstrated multichannel recording capability with good device conformability to the muscle surface during contraction. Important and promising applications will be found in neural prostheses, functional electrical stimulation (FES), and basic electrophysiology research.
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Affiliation(s)
- Liang Guo
- Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA 30332 USA.
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46
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James T, Mannoor MS, Ivanov DV. BioMEMS -Advancing the Frontiers of Medicine. SENSORS (BASEL, SWITZERLAND) 2008; 8:6077-6107. [PMID: 27873858 PMCID: PMC3705549 DOI: 10.3390/s8096077] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/28/2008] [Revised: 09/16/2008] [Accepted: 09/24/2008] [Indexed: 12/22/2022]
Abstract
Biological and medical application of micro-electro-mechanical-systems (MEMS) is currently seen as an area of high potential impact. Integration of biology and microtechnology has resulted in the development of a number of platforms for improving biomedical and pharmaceutical technologies. This review provides a general overview of the applications and the opportunities presented by MEMS in medicine by classifying these platforms according to their applications in the medical field.
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Affiliation(s)
- Teena James
- Microelectronics Research Center and New Jersey Institute of Technology, Newark, NJ, U.S.A.; E-mail: (M. S. M.)
- Dept of Biomedical Engineering, New Jersey Institute of Technology, Newark, NJ, U.S.A.; E-mail: (M. S. M.)
| | - Manu Sebastian Mannoor
- Microelectronics Research Center and New Jersey Institute of Technology, Newark, NJ, U.S.A.; E-mail: (M. S. M.)
- Dept of Biomedical Engineering, New Jersey Institute of Technology, Newark, NJ, U.S.A.; E-mail: (M. S. M.)
| | - Dentcho V. Ivanov
- Microelectronics Research Center and New Jersey Institute of Technology, Newark, NJ, U.S.A.; E-mail: (M. S. M.)
- Dept of Biomedical Engineering, New Jersey Institute of Technology, Newark, NJ, U.S.A.; E-mail: (M. S. M.)
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