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Silva DF, Melo ALP, Uchôa AFC, Pereira GMA, Alves AEF, Vasconcellos MC, Xavier-Júnior FH, Passos MF. Biomedical Approach of Nanotechnology and Biological Risks: A Mini-Review. Int J Mol Sci 2023; 24:16719. [PMID: 38069043 PMCID: PMC10706257 DOI: 10.3390/ijms242316719] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2023] [Revised: 11/10/2023] [Accepted: 11/20/2023] [Indexed: 12/18/2023] Open
Abstract
Nanotechnology has played a prominent role in biomedical engineering, offering innovative approaches to numerous treatments. Notable advances have been observed in the development of medical devices, contributing to the advancement of modern medicine. This article briefly discusses key applications of nanotechnology in tissue engineering, controlled drug release systems, biosensors and monitoring, and imaging and diagnosis. The particular emphasis on this theme will result in a better understanding, selection, and technical approach to nanomaterials for biomedical purposes, including biological risks, security, and biocompatibility criteria.
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Affiliation(s)
- Debora F. Silva
- Technological Development Group in Biopolymers and Biomaterials from the Amazon, Graduate Program in Materials Science and Engineering, Federal University of Para, Ananindeua 67130-660, Brazil;
| | - Ailime L. P. Melo
- Technological Development Group in Biopolymers and Biomaterials from the Amazon, Graduate Program in Biotechnology, Federal University of Para, Belem 66075-110, Brazil
| | - Ana F. C. Uchôa
- Pharmaceutical Biotechnology Laboratory (BioTecFarm), Department of Pharmaceutical Sciences, Federal University of Paraíba, João Pessoa 58051-900, Brazil; (A.F.C.U.); (F.H.X.-J.)
| | - Graziela M. A. Pereira
- Pharmaceutical Biotechnology Laboratory (BioTecFarm), Department of Pharmaceutical Sciences, Federal University of Paraíba, João Pessoa 58051-900, Brazil; (A.F.C.U.); (F.H.X.-J.)
| | - Alisson E. F. Alves
- Post-Graduate Program in Bioactive Natural and Synthetic Products, Federal University of Paraíba, João Pessoa 58051-900, Brazil;
| | | | - Francisco H. Xavier-Júnior
- Pharmaceutical Biotechnology Laboratory (BioTecFarm), Department of Pharmaceutical Sciences, Federal University of Paraíba, João Pessoa 58051-900, Brazil; (A.F.C.U.); (F.H.X.-J.)
- Post-Graduate Program in Bioactive Natural and Synthetic Products, Federal University of Paraíba, João Pessoa 58051-900, Brazil;
| | - Marcele F. Passos
- Technological Development Group in Biopolymers and Biomaterials from the Amazon, Graduate Program in Materials Science and Engineering, Federal University of Para, Ananindeua 67130-660, Brazil;
- Technological Development Group in Biopolymers and Biomaterials from the Amazon, Graduate Program in Biotechnology, Federal University of Para, Belem 66075-110, Brazil
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Zeng Q, Yu S, Fan Z, Huang Y, Song B, Zhou T. Nanocone-Array-Based Platinum-Iridium Oxide Neural Microelectrodes: Structure, Electrochemistry, Durability and Biocompatibility Study. NANOMATERIALS (BASEL, SWITZERLAND) 2022; 12:nano12193445. [PMID: 36234573 PMCID: PMC9565584 DOI: 10.3390/nano12193445] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Revised: 09/23/2022] [Accepted: 09/28/2022] [Indexed: 05/14/2023]
Abstract
Neural interfaces provide a window for bio-signal modulation and recording with the assistance of neural microelectrodes. However, shrinking the size of electrodes results in high electrochemical impedance and low capacitance, thus limiting the stimulation/recording efficiency. In order to achieve critical stability and low power consumption, here, nanocone-shaped platinum (Pt) with an extensive surface area is proposed as an adhesive layer on a bare Pt substrate, followed by the deposition of a thin layer of iridium oxide (IrOx) to fabricate high-performance nanocone-array-based Pt-IrOx neural microelectrodes (200 μm in diameter). A uniform nanocone-shaped Pt with significant roughness is created via controlling the ratio of NH4+ and Pt4+ ions in the electrolyte, which can be widely applicable for batch production on multichannel flexible microelectrode arrays (fMEAs) and various substrates with different dimensions. The Pt-IrOx nanocomposite-coated microelectrode presents a significantly low impedance down to 0.72 ± 0.04 Ω cm2 at 1 kHz (reduction of ~92.95%). The cathodic charge storage capacity (CSCc) and charge injection capacity (CIC) reaches up to 52.44 ± 2.53 mC cm-2 and 4.39 ± 0.36 mC cm-2, respectively. Moreover, superior chronic stability and biocompatibility are also observed. The modified microelectrodes significantly enhance the adhesion of microglia, the major immune cells in the central nervous system. Therefore, such a coating strategy presents great potential for biomedical and other practical applications.
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Affiliation(s)
- Qi Zeng
- Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
- College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen 518061, China
- Correspondence: (Q.Z.); (B.S.); (T.Z.)
| | - Shoujun Yu
- Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
| | - Zihui Fan
- Institutes of Biomedical Sciences, Fudan University, Shanghai 200032, China
| | - Yubin Huang
- Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
| | - Bing Song
- Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
- Correspondence: (Q.Z.); (B.S.); (T.Z.)
| | - Tian Zhou
- Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
- Correspondence: (Q.Z.); (B.S.); (T.Z.)
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3
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Ahn J, Cha S, Choi KE, Kim SW, Yoo Y, Goo YS. Correlated Activity in the Degenerate Retina Inhibits Focal Response to Electrical Stimulation. Front Cell Neurosci 2022; 16:889663. [PMID: 35602554 PMCID: PMC9114441 DOI: 10.3389/fncel.2022.889663] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Accepted: 04/13/2022] [Indexed: 11/24/2022] Open
Abstract
Retinal prostheses have shown some clinical success in patients with retinitis pigmentosa and age-related macular degeneration. However, even after the implantation of a retinal prosthesis, the patient’s visual acuity is at best less than 20/420. Reduced visual acuity may be explained by a decrease in the signal-to-noise ratio due to the spontaneous hyperactivity of retinal ganglion cells (RGCs) found in degenerate retinas. Unfortunately, abnormal retinal rewiring, commonly observed in degenerate retinas, has rarely been considered for the development of retinal prostheses. The purpose of this study was to investigate the aberrant retinal network response to electrical stimulation in terms of the spatial distribution of the electrically evoked RGC population. An 8 × 8 multielectrode array was used to measure the spiking activity of the RGC population. RGC spikes were recorded in wild-type [C57BL/6J; P56 (postnatal day 56)], rd1 (P56), rd10 (P14 and P56) mice, and macaque [wild-type and drug-induced retinal degeneration (RD) model] retinas. First, we performed a spike correlation analysis between RGCs to determine RGC connectivity. No correlation was observed between RGCs in the control group, including wild-type mice, rd10 P14 mice, and wild-type macaque retinas. In contrast, for the RD group, including rd1, rd10 P56, and RD macaque retinas, RGCs, up to approximately 400–600 μm apart, were significantly correlated. Moreover, to investigate the RGC population response to electrical stimulation, the number of electrically evoked RGC spikes was measured as a function of the distance between the stimulation and recording electrodes. With an increase in the interelectrode distance, the number of electrically evoked RGC spikes decreased exponentially in the control group. In contrast, electrically evoked RGC spikes were observed throughout the retina in the RD group, regardless of the inter-electrode distance. Taken together, in the degenerate retina, a more strongly coupled retinal network resulted in the widespread distribution of electrically evoked RGC spikes. This finding could explain the low-resolution vision in prosthesis-implanted patients.
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Affiliation(s)
- Jungryul Ahn
- Department of Physiology, Chungbuk National University School of Medicine, Cheongju, South Korea
| | - Seongkwang Cha
- Department of Physiology, Chungbuk National University School of Medicine, Cheongju, South Korea
| | - Kwang-Eon Choi
- Department of Ophthalmology, Korea University College of Medicine, Seoul, South Korea
| | - Seong-Woo Kim
- Department of Ophthalmology, Korea University College of Medicine, Seoul, South Korea
- *Correspondence: Seong-Woo Kim,
| | - Yongseok Yoo
- Department of Electronics Engineering, Incheon National University, Incheon, South Korea
- Yongseok Yoo,
| | - Yong Sook Goo
- Department of Physiology, Chungbuk National University School of Medicine, Cheongju, South Korea
- Yong Sook Goo,
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Tringides CM, Mooney DJ. Materials for Implantable Surface Electrode Arrays: Current Status and Future Directions. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2107207. [PMID: 34716730 DOI: 10.1002/adma.202107207] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Revised: 10/26/2021] [Indexed: 06/13/2023]
Abstract
Surface electrode arrays are mainly fabricated from rigid or elastic materials, and precisely manipulated ductile metal films, which offer limited stretchability. However, the living tissues to which they are applied are nonlinear viscoelastic materials, which can undergo significant mechanical deformation in dynamic biological environments. Further, the same arrays and compositions are often repurposed for vastly different tissues rather than optimizing the materials and mechanical properties of the implant for the target application. By first characterizing the desired biological environment, and then designing a technology for a particular organ, surface electrode arrays may be more conformable, and offer better interfaces to tissues while causing less damage. Here, the various materials used in each component of a surface electrode array are first reviewed, and then electrically active implants in three specific biological systems, the nervous system, the muscular system, and skin, are described. Finally, the fabrication of next-generation surface arrays that overcome current limitations is discussed.
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Affiliation(s)
- Christina M Tringides
- Harvard Program in Biophysics, Harvard University, Cambridge, MA, 02138, USA
- Harvard-MIT Division in Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Cambridge, MA, 02138, USA
| | - David J Mooney
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Cambridge, MA, 02138, USA
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, 02138, USA
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Song X, Qiu S, Shivdasani MN, Zhou F, Liu Z, Ma S, Chai X, Chen Y, Cai X, Guo T, Li L. An in-silico analysis of electrically-evoked responses of midget and parasol retinal ganglion cells in different retinal regions. J Neural Eng 2022; 19. [PMID: 35255486 DOI: 10.1088/1741-2552/ac5b18] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Accepted: 03/07/2022] [Indexed: 11/12/2022]
Abstract
BACKGROUND Visual outcomes provided by present retinal prostheses that primarily target retinal ganglion cells (RGCs) through epiretinal stimulation remain rudimentary, partly due to the limited knowledge of retinal responses under electrical stimulation. Better understanding of how different retinal regions can be quantitatively controlled with high spatial accuracy, will be beneficial to the design of micro-electrode arrays (MEAs) and stimulation strategies for next-generation wide-view, high-resolution epiretinal implants. METHODS A computational model was developed to assess neural activity at different eccentricities (2 mm and 5 mm) within the human retina. This model included midget and parasol RGCs with anatomically accurate cell distribution and cell-specific morphological information. We then performed in silico investigations of region-specific RGC responses to epiretinal electrical stimulation using varied electrode sizes (5 µm - 210 µm diameter), emulating both commercialized retinal implants and recently-developed prototype devices. RESULTS Our model of epiretinal stimulation predicted RGC population excitation analogous to the complex percepts reported in human subjects. Following this, our simulations suggest that midget and parasol RGCs have characteristic regional differences in excitation under preferred electrode sizes. Relatively central (2 mm) regions demonstrated higher number of excited RGCs but lower overall activated receptive field (RF) areas under the same stimulus amplitudes (two-way ANOVA, p < 0.05). Furthermore, the activated RGC numbers per unit active RF area (number-RF ratio) were significantly higher in central than in peripheral regions, and higher in the midget than in the parasol population under all tested electrode sizes (two-way ANOVA, p < 0.05). Our simulations also suggested that smaller electrodes exhibit a higher range of controllable stimulation parameters to achieve pre-defined performance of RGC excitation. ..
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Affiliation(s)
- Xiaoyu Song
- , Shanghai Jiao Tong University, Dongchuan Road, Shanghai Minhang District No. 800, Shanghai, 200240, CHINA
| | - Shirong Qiu
- Shanghai Jiao Tong University, Dongchuan Road, Shanghai Minhang District No. 800, Shanghai, 200240, CHINA
| | - Mohit N Shivdasani
- Graduate School of Biomedical Engineering, University of New South Wales, Lower Ground, Samuels Building (F25), Kensington, New South Wales, 2052, AUSTRALIA
| | - Feng Zhou
- Shanghai Jiao Tong University, Dongchuan Road, Shanghai Minhang District No. 800, Shanghai, 200240, CHINA
| | - Zhengyang Liu
- Shanghai Jiao Tong University, Dongchuan Road, Shanghai Minhang District No. 800, Shanghai, 200240, CHINA
| | - Saidong Ma
- Shanghai Jiao Tong University, Dongchuan Road, Shanghai Minhang District No. 800, Shanghai, 200240, CHINA
| | - Xinyu Chai
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai 200240, Shanghai, 200240, CHINA
| | - Yao Chen
- Department of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai 200040, Shanghai, 200240, CHINA
| | - Xuan Cai
- Department of Ophthalmology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, 600 Yishan Road, Shanghai, Shanghai, 200233, CHINA
| | - Tianruo Guo
- the University of New South Wales, Lower Ground, Samuels Building (F25), Sydney, 2052, AUSTRALIA
| | - Liming Li
- Shanghai Jiao Tong University, Dongchuan Road, Shanghai Minhang District No. 800, Shanghai, 200240, CHINA
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6
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IC-Based Rectification Circuit Techniques for Biomedical Energy-Harvesting Applications. MICROMACHINES 2022; 13:mi13030411. [PMID: 35334703 PMCID: PMC8953514 DOI: 10.3390/mi13030411] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Revised: 03/02/2022] [Accepted: 03/03/2022] [Indexed: 11/16/2022]
Abstract
Energy harvesting can be achieved through many different mechanisms. Such technology has been drawing researchers’ attention to its practical applications for a decade, as it can be widely applied to countless scenarios. It steals the show in the modern development of the biomedical electronics, especially implantable applications, as it allows the patients to move freely without restriction. To prolong lifetime of the battery inside/outside a patient’s body, the electrical conversion efficiency of the electronic implant is of primary importance in energy harvesting. The conversion can be achieved by a so-called miniaturized rectification circuit (also known as “rectifier”). This study aims to compare different state-of-the-art techniques focusing on the conversion efficiency of the rectification. Particular emphasis is put on semiconductor-based circuits capable of being integrated with tiny chips on the implants.
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7
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Zeng Q, Li X, Zhang S, Deng C, Wu T. Think big, see small—A review of nanomaterials for neural interfaces. NANO SELECT 2021. [DOI: 10.1002/nano.202100256] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Affiliation(s)
- Qi Zeng
- Shenzhen Institute of Advanced Technology Chinese Academy of Sciences Shenzhen P.R. China
- College of Physics and Optoelectronic Engineering Shenzhen University Shenzhen P.R. China
| | - Xiaojian Li
- Shenzhen Institute of Advanced Technology Chinese Academy of Sciences Shenzhen P.R. China
- Key Laboratory of Brain Connectome and Manipulation Chinese Academy of Sciences Shenzhen‐Hong Kong Institute of Brain Science‐Shenzhen Fundamental Research Institutions Shenzhen P.R. China
| | - Shiyun Zhang
- Shenzhen Institute of Advanced Technology Chinese Academy of Sciences Shenzhen P.R. China
| | - Chunshan Deng
- Shenzhen Institute of Advanced Technology Chinese Academy of Sciences Shenzhen P.R. China
- Key Laboratory of Brain Connectome and Manipulation Chinese Academy of Sciences Shenzhen‐Hong Kong Institute of Brain Science‐Shenzhen Fundamental Research Institutions Shenzhen P.R. China
| | - Tianzhun Wu
- Shenzhen Institute of Advanced Technology Chinese Academy of Sciences Shenzhen P.R. China
- Key Laboratory of Health Bioinformatics Chinese Academy of Sciences Shenzhen P.R. China
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8
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Li W, Xu Z, Wang H, Wu T. The Effect of Electrical Stimulation on the Response of Mouse Retinal Ganglion Cells. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2021; 2021:5704-5708. [PMID: 34892416 DOI: 10.1109/embc46164.2021.9630580] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Retinal prostheses can restore the basic visual function of patients with retinal degeneration, which relies on effective electrical stimulation to evoke the physiological activities of retinal ganglion cells (RGCs). Current electrical stimulation strategies suffer from unstable effects and insufficient stimulation positions. Therefore, it is crucial to determine the optimal parameters for precise and safe electrical stimulation. Biphasic voltages (cathode-first) with a pulse width of 25 ms and different amplitudes were used to ex vivo stimulate RGCs of three wild-type (WT) mice using a commercial microelectrode array (MEA) recording system. Based on a facile and efficient spike sorting method, comprehensive statistics of RGCs response types were performed, and the influence of electrical stimulation on RGCs response status was analyzed. There were three types of RGCs response measured from the retinas of three WT mice, and the proportions were calculated to be 91.5%, 3.11% and 5.39%, respectively. This work can provide an in-depth understanding of the internal effects of electrical stimulation and RGCs response, with the potential as a useful guidance for optimizing parameters of electrical stimulation strategies in retinal prostheses.
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9
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Xie H, Wang Y, Ye Z, Fang S, Xu Z, Wu T, Chan LLH. Monitoring Cortical Response and Electrode-Retina Impedance Under Epiretinal Stimulation in Rats. IEEE Trans Neural Syst Rehabil Eng 2021; 29:1178-1187. [PMID: 34152987 DOI: 10.1109/tnsre.2021.3090904] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Retinal prosthesis can restore partial vision in patients with retinal degenerative diseases such as retinitis pigmentosa and age-related macular degeneration. Epiretinal prosthesis is one of three therapeutic approaches, which received regulatory approval several years ago. The thresholds of an epiretinal stimulation is partly determined by the size of the physical gap between the electrode and the retina after implantation. Precise positioning of epiretinal stimulating electrode array is still a challenging task. In this study, we demonstrate an approach to positioning epiretinal prostheses for an optimal response at the cortical output by monitoring both the impedance at the electrode-retina interface and the evoked-potential at the cortical level. We implanted a single-channel electrode on the epiretinal surface in adult rats, acutely, guided by both the impedance at the electrode-retina interface and by electrically evoked potentials (EEPs) in the visual cortex during retinal stimulation. We observe that impedance monotonously increases with decreasing electrode-retina distance, but that the strongest cortical responses were achieved at intermediate impedance levels. When the electrode penetrates the retina, the impedance keeps increasing. The effect of stimulation on the retina changes from epiretinal paradigm to intra-retinal paradigm and a decrease in cortical activation is observed. It is found that high impedance is not always favorable to elicit best cortical responses. Histopathological results showed that the electrode was placed at the intra-retinal space at high impedance value. These results show that monitoring impedance at the electrode-retina interface is necessary but not sufficient in obtaining strong evoked-potentials at the cortical level. Monitoring the cortical EEPs together with the impedance can improve the safety of implantation as well as efficacy of stimulation in the next generation of retinal implants.
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10
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Li W, Qin S, Lu Y, Wang H, Xu Z, Wu T. A facile and comprehensive algorithm for electrical response identification in mouse retinal ganglion cells. PLoS One 2021; 16:e0246547. [PMID: 33705406 PMCID: PMC7951861 DOI: 10.1371/journal.pone.0246547] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2020] [Accepted: 01/20/2021] [Indexed: 12/01/2022] Open
Abstract
Retinal prostheses can restore the basic visual function of patients with retinal degeneration, which relies on effective electrical stimulation to evoke the physiological activities of retinal ganglion cells (RGCs). Current electrical stimulation strategies have defects such as unstable effects and insufficient stimulation positions, therefore, it is crucial to determine the optimal pulse parameters for precise and safe electrical stimulation. Biphasic voltages (cathode-first) with a pulse width of 25 ms and different amplitudes were used to ex vivo stimulate RGCs of three wild-type (WT) mice using a commercial microelectrode array (MEA) recording system. An algorithm is developed to automatically realize both spike-sorting and electrical response identification for the spike signals recorded. Measured from three WT mouse retinas, the total numbers of RGC units and responsive RGC units were 1193 and 151, respectively. In addition, the optimal pulse amplitude range for electrical stimulation was determined to be 0.43 V-1.3 V. The processing results of the automatic algorithm we proposed shows high consistency with those using traditional manual processing. We anticipate the new algorithm can not only speed up the elaborate electrophysiological data processing, but also optimize pulse parameters for the electrical stimulation strategy of neural prostheses.
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Affiliation(s)
- Wanying Li
- Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Shan Qin
- Shenzhen Shekou People’s Hospital, Shenzhen, China
| | - Yijie Lu
- Shenzhen Aier Eye Hospital, Shenzhen, China
| | - Hao Wang
- Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Zhen Xu
- Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
- * E-mail: (TZW); (ZX)
| | - Tianzhun Wu
- Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
- * E-mail: (TZW); (ZX)
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11
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Titchener SA, Kvansakul J, Shivdasani MN, Fallon JB, Nayagam DAX, Epp SB, Williams CE, Barnes N, Kentler WG, Kolic M, Baglin EK, Ayton LN, Abbott CJ, Luu CD, Allen PJ, Petoe MA. Oculomotor Responses to Dynamic Stimuli in a 44-Channel Suprachoroidal Retinal Prosthesis. Transl Vis Sci Technol 2020; 9:31. [PMID: 33384885 PMCID: PMC7757638 DOI: 10.1167/tvst.9.13.31] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Accepted: 11/12/2020] [Indexed: 12/20/2022] Open
Abstract
Purpose To investigate oculomotor behavior in response to dynamic stimuli in retinal implant recipients. Methods Three suprachoroidal retinal implant recipients performed a four-alternative forced-choice motion discrimination task over six sessions longitudinally. Stimuli were a single white bar (“moving bar”) or a series of white bars (“moving grating”) sweeping left, right, up, or down across a 42″ monitor. Performance was compared with normal video processing and scrambled video processing (randomized image-to-electrode mapping to disrupt spatiotemporal structure). Eye and head movement was monitored throughout the task. Results Two subjects had diminished performance with scrambling, suggesting retinotopic discrimination was used in the normal condition and made smooth pursuit eye movements congruent to the moving bar stimulus direction. These two subjects also made stimulus-related eye movements resembling optokinetic reflex (OKR) for moving grating stimuli, but the movement was incongruent with stimulus direction. The third subject was less adept at the task, appeared primarily reliant on head position cues (head movements were congruent to stimulus direction), and did not exhibit retinotopic discrimination and associated eye movements. Conclusions Our observation of smooth pursuit indicates residual functionality of cortical direction-selective circuits and implies a more naturalistic perception of motion than expected. A distorted OKR implies improper functionality of retinal direction-selective circuits, possibly due to retinal remodeling or the non-selective nature of the electrical stimulation. Translational Relevance Retinal implant users can make naturalistic eye movements in response to moving stimuli, highlighting the potential for eye tracker feedback to improve perceptual localization and image stabilization in camera-based visual prostheses.
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Affiliation(s)
- Samuel A Titchener
- Bionics Institute, East Melbourne, Australia.,Medical Bionics Department, University of Melbourne, Melbourne, Australia
| | - Jessica Kvansakul
- Bionics Institute, East Melbourne, Australia.,Medical Bionics Department, University of Melbourne, Melbourne, Australia
| | - Mohit N Shivdasani
- Graduate School of Biomedical Engineering, University of New South Wales, Kensington, Australia.,Bionics Institute, East Melbourne, Australia
| | - James B Fallon
- Bionics Institute, East Melbourne, Australia.,Medical Bionics Department, University of Melbourne, Melbourne, Australia
| | - D A X Nayagam
- Bionics Institute, East Melbourne, Australia.,Department of Pathology, University of Melbourne, St. Vincent's Hospital, Melbourne, Australia
| | | | - Chris E Williams
- Bionics Institute, East Melbourne, Australia.,Medical Bionics Department, University of Melbourne, Melbourne, Australia
| | - Nick Barnes
- Data61, CSIRO, Canberra, Australia.,Research School of Engineering, Australian National University, Canberra, Australia
| | - William G Kentler
- Department of Biomedical Engineering, University of Melbourne, Melbourne, Australia
| | - Maria Kolic
- Centre for Eye Research Australia, Royal Victorian Eye & Ear Hospital, Melbourne, Australia
| | - Elizabeth K Baglin
- Centre for Eye Research Australia, Royal Victorian Eye & Ear Hospital, Melbourne, Australia
| | - Lauren N Ayton
- Centre for Eye Research Australia, Royal Victorian Eye & Ear Hospital, Melbourne, Australia
| | - Carla J Abbott
- Centre for Eye Research Australia, Royal Victorian Eye & Ear Hospital, Melbourne, Australia.,Ophthalmology, Department of Surgery, University of Melbourne, Melbourne, Australia
| | - Chi D Luu
- Centre for Eye Research Australia, Royal Victorian Eye & Ear Hospital, Melbourne, Australia.,Ophthalmology, Department of Surgery, University of Melbourne, Melbourne, Australia
| | - Penelope J Allen
- Centre for Eye Research Australia, Royal Victorian Eye & Ear Hospital, Melbourne, Australia.,Ophthalmology, Department of Surgery, University of Melbourne, Melbourne, Australia
| | - Matthew A Petoe
- Bionics Institute, East Melbourne, Australia.,Medical Bionics Department, University of Melbourne, Melbourne, Australia
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12
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Shire DB, Gingerich MD, Wong PI, Skvarla M, Cogan SF, Chen J, Wang W, Rizzo JF. Micro-Fabrication of Components for a High-Density Sub-Retinal Visual Prosthesis. MICROMACHINES 2020; 11:mi11100944. [PMID: 33086504 PMCID: PMC7603138 DOI: 10.3390/mi11100944] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/29/2020] [Revised: 10/10/2020] [Accepted: 10/13/2020] [Indexed: 01/30/2023]
Abstract
We present a retrospective of unique micro-fabrication problems and solutions that were encountered through over 10 years of retinal prosthesis product development, first for the Boston Retinal Implant Project initiated at the Massachusetts Institute of Technology and at Harvard Medical School’s teaching hospital, the Massachusetts Eye and Ear—and later at the startup company Bionic Eye Technologies, by some of the same personnel. These efforts culminated in the fabrication and assembly of 256+ channel visual prosthesis devices having flexible multi-electrode arrays that were successfully implanted sub-retinally in mini-pig animal models as part of our pre-clinical testing program. We report on the processing of the flexible multi-layered, planar and penetrating high-density electrode arrays, surgical tools for sub-retinal implantation, and other parts such as coil supports that facilitated the implantation of the peri-ocular device components. We begin with an overview of the implantable portion of our visual prosthesis system design, and describe in detail the micro-fabrication methods for creating the parts of our system that were assembled outside of our hermetically-sealed electronics package. We also note the unique surgical challenges that sub-retinal implantation of our micro-fabricated components presented, and how some of those issues were addressed through design, materials selection, and fabrication approaches.
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Affiliation(s)
- Douglas B. Shire
- Bionic Eye Technologies, Inc., Ithaca, NY 14850, USA; (M.D.G.); (P.I.W.)
- Correspondence: ; Tel.: +1-607-339-7085
| | | | - Patricia I. Wong
- Bionic Eye Technologies, Inc., Ithaca, NY 14850, USA; (M.D.G.); (P.I.W.)
| | - Michael Skvarla
- Cornell NanoScale Science and Technology Facility, Ithaca, NY 14853, USA;
| | - Stuart F. Cogan
- Department of Bioengineering, University of Texas, Dallas, Richardson, TX 75080, USA;
| | - Jinghua Chen
- Department of Ophthalmology, University of Florida, Gainesville, FL 32611, USA;
| | - Wei Wang
- Department of Ophthalmology, University of Louisville, Louisville, KY 40292, USA;
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13
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Wang H, Wu T, Zeng Q, Lee C. A Review and Perspective for the Development of Triboelectric Nanogenerator (TENG)-Based Self-Powered Neuroprosthetics. MICROMACHINES 2020; 11:E865. [PMID: 32961902 PMCID: PMC7570145 DOI: 10.3390/mi11090865] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 09/10/2020] [Accepted: 09/15/2020] [Indexed: 02/07/2023]
Abstract
Neuroprosthetics have become a powerful toolkit for clinical interventions of various diseases that affect the central nervous or peripheral nervous systems, such as deep brain stimulation (DBS), functional electrical stimulation (FES), and vagus nerve stimulation (VNS), by electrically stimulating different neuronal structures. To prolong the lifetime of implanted devices, researchers have developed power sources with different approaches. Among them, the triboelectric nanogenerator (TENG) is the only one to achieve direct nerve stimulations, showing great potential in the realization of a self-powered neuroprosthetic system in the future. In this review, the current development and progress of the TENG-based stimulation of various kinds of nervous systems are systematically summarized. Then, based on the requirements of the neuroprosthetic system in a real application and the development of current techniques, a perspective of a more sophisticated neuroprosthetic system is proposed, which includes components of a thin-film TENG device with a biocompatible package, an amplification circuit to enhance the output, and a self-powered high-frequency switch to generate high-frequency current pulses for nerve stimulations. Then, we review and evaluate the recent development and progress of each part.
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Affiliation(s)
- Hao Wang
- Institute of Biomedical & Health Engineering, Shenzhen Institutes of Advanced Technology (SIAT), Chinese Academy of Sciences (CAS), Shenzhen 518035, China; (T.W.); (Q.Z.)
| | - Tianzhun Wu
- Institute of Biomedical & Health Engineering, Shenzhen Institutes of Advanced Technology (SIAT), Chinese Academy of Sciences (CAS), Shenzhen 518035, China; (T.W.); (Q.Z.)
- Key Laboratory of Health Bioinformatics, Chinese Academy of Sciences, Shenzhen 518035, China
| | - Qi Zeng
- Institute of Biomedical & Health Engineering, Shenzhen Institutes of Advanced Technology (SIAT), Chinese Academy of Sciences (CAS), Shenzhen 518035, China; (T.W.); (Q.Z.)
| | - Chengkuo Lee
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117576, Singapore;
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14
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French P. In-Vivo Microsystems: A Review. SENSORS (BASEL, SWITZERLAND) 2020; 20:E4953. [PMID: 32883011 PMCID: PMC7506850 DOI: 10.3390/s20174953] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Revised: 08/11/2020] [Accepted: 08/13/2020] [Indexed: 12/25/2022]
Abstract
In-vivo sensors yield valuable medical information by measuring directly on the living tissue of a patient. These devices can be surface or implant devices. Electrical activity in the body, from organs or muscles can be measured using surface electrodes. For short term internal devices, catheters are used. These include cardiac catheter (in blood vessels) and bladder catheters. Due to the size and shape of the catheters, silicon devices provided an excellent solution for sensors. Since many cardiac catheters are disposable, the high volume has led to lower prices of the silicon sensors. Many catheters use a single sensor, but silicon offers the opportunity to have multi sensors in a single catheter, while maintaining small size. The cardiac catheter is usually inserted for a maximum of 72 h. Some devices may be used for a short-to-medium period to monitor parameters after an operation or injury (1-4 weeks). Increasingly, sensing, and actuating, devices are being applied to longer term implants for monitoring a range of parameters for chronic conditions. Devices for longer term implantation presented additional challenges due to the harshness of the environment and the stricter regulations for biocompatibility and safety. This paper will examine the three main areas of application for in-vivo devices: surface devices and short/medium-term and long-term implants. The issues of biocompatibility and safety will be discussed.
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Affiliation(s)
- Paddy French
- Laboratory for Bioelectronics, Faculty of Electrical Engineering, Mathematics and Computer Science, TU Delft, Mekelweg 4, 2628CD Delft, The Netherlands
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15
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Seo HW, Kim N, Kim S. Fabrication of Subretinal 3D Microelectrodes with Hexagonal Arrangement. MICROMACHINES 2020; 11:mi11050467. [PMID: 32365472 PMCID: PMC7281732 DOI: 10.3390/mi11050467] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/29/2020] [Revised: 04/26/2020] [Accepted: 04/27/2020] [Indexed: 02/01/2023]
Abstract
This study presents the fabrication of three-dimensional (3D) microelectrodes for subretinal stimulation, to accommodate adjacent return electrodes surrounding a stimulating electrode. For retinal prosthetic devices, the arrangement of return electrodes, the electrode size and spacing should be considered together, to reduce the undesired dissipation of electric currents. Here, we applied the hexagonal arrangement to the microelectrode array for the localized activation of retinal cells and better visual acuity. To provide stimuli more efficiently to non-spiking neurons, a 3D structure was created through a customized pressing process, utilizing the elastic property of the materials used in the fabrication processes. The diameter and pitch of the Pt-coated electrodes were 150 μm and 350 μm, respectively, and the height of the protruded electrodes was around 20 μm. The array consisted of 98 hexagonally arranged electrodes, supported by a flexible and transparent polydimethylsiloxane (PDMS) base, with a thickness of 140 μm. Also, the array was coated with 2 μm-thick parylene-C, except the active electrode sites, for more focused stimulation. Finally, the electrochemical properties of the fabricated microelectrodes were characterized, resulting in the mean impedance of 384.87 kΩ at 1 kHz and the charge storage capacity (CSC) of 2.83 mC·cm−2. The fabricated microelectrodes are to be combined with an integrated circuit (IC) for additional in vitro and in vivo experiments.
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Affiliation(s)
| | | | - Sohee Kim
- Correspondence: ; Tel.: +82-53-785-6217
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16
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Li R, Du Z, Qian X, Li Y, Martinez-Camarillo JC, Jiang L, Humayun MS, Chen Z, Zhou Q. High resolution optical coherence elastography of retina under prosthetic electrode. Quant Imaging Med Surg 2020; 11:918-927. [PMID: 33654665 DOI: 10.21037/qims-20-1137] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Background Quantitatively investigating the biomechanics of retina with a retinal prosthetic electrode, we explored the effects of the prosthetic electrode on the retina, and further supplemented data for a potential clinical trial. Methods Biomechanical properties were assessed with a high resolution optical coherence tomography (OCT) based elastography (OCE) system. A shaker was used to initiate elastic waves and an OCT system was used to track axial displacement along with wave propagation. Rabbits received surgery to implant the retinal prosthetic electrode, and elastic wave speed was measured before and after implantation; anatomical B-mode images were also acquired. Results Spatial-temporal maps of each layer in retina with and without prosthetic electrodes were acquired. Elastic wave speed of nerve fiber to inner plexiform layer, inner nuclear to outer nuclear layer, retinal pigmented epithelium layer and choroid to sclera layer without prosthetic electrode were found to be 3.66±0.36, 5.33±0.07, 6.85±0.37, and 9.69±0.24 m/s, respectively. With prosthetic electrode, the elastic wave speed was found to be 4.09±0.26, 5.14±0.11, 6.88±0.70, and 9.99±0.73 m/s, respectively in each layer. Conclusions Our results show that the elastic wave speed in each layer of retina is slightly faster with the retinal electrode, and further demonstrate that the retinal prosthetic electrode does not affect biomechanical properties significantly. In the future, we expect OCE technology to be used by clinicians where it could become part of routine testing and evaluation of the biomechanical properties of the retina in response to long term use of prosthetic electrodes in patients.
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Affiliation(s)
- Runze Li
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, USA.,USC Roski Eye Institute, University of Southern California, Los Angeles, CA, USA
| | - Zhaodong Du
- USC Roski Eye Institute, University of Southern California, Los Angeles, CA, USA
| | - Xuejun Qian
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, USA.,USC Roski Eye Institute, University of Southern California, Los Angeles, CA, USA
| | - Yan Li
- Beckman Laser Institute, University of California, Irvine, CA, USA.,Department of Biomedical Engineering, University of California, Irvine, CA, USA
| | | | - Laiming Jiang
- USC Roski Eye Institute, University of Southern California, Los Angeles, CA, USA
| | - Mark S Humayun
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, USA.,USC Roski Eye Institute, University of Southern California, Los Angeles, CA, USA
| | - Zhongping Chen
- Beckman Laser Institute, University of California, Irvine, CA, USA.,Department of Biomedical Engineering, University of California, Irvine, CA, USA
| | - Qifa Zhou
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, USA.,USC Roski Eye Institute, University of Southern California, Los Angeles, CA, USA
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17
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Li W, Qiu Z. Editorial for the Special Issue on Implantable Microdevices. MICROMACHINES 2019; 10:mi10090603. [PMID: 31547422 PMCID: PMC6780928 DOI: 10.3390/mi10090603] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Accepted: 09/11/2019] [Indexed: 11/16/2022]
Affiliation(s)
- Wen Li
- Department of Electrical and Computer Engineering, Michigan State University, East Lansing, MI 48824, USA.
- Department of Biomedical Engineering, Michigan State University, East Lansing, MI 48824, USA.
- Institute for Quantitative Health Science and Engineering, Michigan State University, East Lansing, MI 48824, USA.
| | - Zhen Qiu
- Department of Electrical and Computer Engineering, Michigan State University, East Lansing, MI 48824, USA.
- Department of Biomedical Engineering, Michigan State University, East Lansing, MI 48824, USA.
- Institute for Quantitative Health Science and Engineering, Michigan State University, East Lansing, MI 48824, USA.
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