Publicação
Development of graphene electrodes for artificial retinas
| Resumo: | Electrical neural interfaces are fundamental for the development of new devices able to improve lost body functions to impaired people. Retinal damage is a common cause of loss of vision, that can be mitigated through retinal implants able to electrically stimulate the nerve cells in response to the incident light. Such electrical contacts should be small and biocompatible, and for this particular application transparency can be an added feature for design flexibility. The main objective of this work is to study the application of graphene as electrodes for artificial retinas, taking advantage of the excellent electrical properties, flexibility and biocompatibility of this material. The graphene was synthesized by chemical vapor deposition, following two approaches: thermal activation (TCVD) and microwave plasma activation (MPCVD). The obtained films were transferred onto different substrates, in order to characterize the graphene by Raman spectroscopy, scanning electron microscopy, sheet resistance measurements, optical transmittance and electrochemical characterization. The flexible implants, composed by four graphene electrodes on polyimide substrates, were produced by microfabrication in a clean room, with the optimization of the respective processes. The characterization of the resulting devices relied on electrochemical techniques such as cyclic voltammetry and electrochemical impedance spectroscopy. The results of this characterization were analyzed in the context of the various microfabrication steps, pointing towards challenges inherent to the compatibility of graphene with the patterning processes employed here. As such, this work opens the door for future developments in the field of artificial retinas, contributing with the identification and study of important practical aspects for the integration of graphene in these devices. |
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| Autores principais: | Almeida, Ana Rita Lourenço de |
| Assunto: | Graphene CVD Electrodes Retinal implants Neuronal interfaces Microfabrication Electrochemistry |
| Ano: | 2022 |
| País: | Portugal |
| Tipo de documento: | dissertação de mestrado |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Universidade de Aveiro |
| Idioma: | inglês |
| Origem: | RIA - Repositório Institucional da Universidade de Aveiro |
| Resumo: | Electrical neural interfaces are fundamental for the development of new devices able to improve lost body functions to impaired people. Retinal damage is a common cause of loss of vision, that can be mitigated through retinal implants able to electrically stimulate the nerve cells in response to the incident light. Such electrical contacts should be small and biocompatible, and for this particular application transparency can be an added feature for design flexibility. The main objective of this work is to study the application of graphene as electrodes for artificial retinas, taking advantage of the excellent electrical properties, flexibility and biocompatibility of this material. The graphene was synthesized by chemical vapor deposition, following two approaches: thermal activation (TCVD) and microwave plasma activation (MPCVD). The obtained films were transferred onto different substrates, in order to characterize the graphene by Raman spectroscopy, scanning electron microscopy, sheet resistance measurements, optical transmittance and electrochemical characterization. The flexible implants, composed by four graphene electrodes on polyimide substrates, were produced by microfabrication in a clean room, with the optimization of the respective processes. The characterization of the resulting devices relied on electrochemical techniques such as cyclic voltammetry and electrochemical impedance spectroscopy. The results of this characterization were analyzed in the context of the various microfabrication steps, pointing towards challenges inherent to the compatibility of graphene with the patterning processes employed here. As such, this work opens the door for future developments in the field of artificial retinas, contributing with the identification and study of important practical aspects for the integration of graphene in these devices. |
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