Development, Formation Mechanism and Electro-stimulated Release Properties of Drug-embedded Implanted Silk/Gelatin/rGO Composite Electrode using Electrgelation

• Main Authors: Lin, Jing-Syu, 林勁旭
• Other Authors: Chen, San-Yuan
• Format: Others
• Language: en_US
• Published: 2019
• Online Access: http://ndltd.ncl.edu.tw/handle/4z852b

碩士 === 國立交通大學 === 材料科學與工程學系所 === 107 === Implantable electrodes have raised great appeal over years with the improvement of neurodegenerative disorders. For brain implant devices, some key factors resulting in the formation of glial scar such as mechanical mismatch, biofouling by astrocytes, and acute injury-induced inflammation should be considered for materials design. Therefore, in our study, a novel technique: electrogelation was developed to fabricate a new implantable electrode with the following features: (1) the electrode should be high Young’s modulus (11~150 MPa) for penetration but subsequently transferred and decreased to low Young’s modulus to become biomimetic brain tissue (50~3200 kPa) after insertion in brain. (2) the electrode fabricated by an innovative electrogelation technique performs better electrochemical properties than the common castingmethod. (3) anti-inflammatory drug (DEX) release can be electrically stimulatedto overcome tissue response. Silk fibroin (SF), extracted from Bombyx mori cocoons, mixed with gelatin and graphene oxide (GO), then added reducing agent to synthesis SF/gelatin/rGO hydrogel solution with different rGO content. After the solution was prepared, the closed-loop anode was immersed in the solution and applied with direct electrical voltage to fabricate the flexible SF/gelatin/rGO composite electrogels formed on the positive electrode with arbitrary shape. The SF/gelatin/rGO composite electrode formed as the electrogels was totally dried. The hydrogen bonding, crystallinity and mechanical properties of e-SgG film electrodes with different ratios of rGO were investigated. The results showed that the e-SgG-2 film with the 1.23% rGO content showed higher Young's modulus under wet conditions and exhibited better electrochemical performance than the casted SgG-2 film. This phenomenon could be attributed to the following reasons: (i) increased crystallinity and β-sheet content (ii) increased hydrogen bonding (iii) sponge-like porous architecture with wrinkled texture and larger surface area of the e-SgG-2 film. In order to reduce the inflammatory response when inserting in brain tissues, the anti-inflammatory drug (DEX) was incorporated to the e-SgG-2 film. In PBS, the rapid degradation of the e-SgG-2 film was not observed. However, during cyclic voltammetry process, the applying AC field could cause the film degradation and resulting the drug release. Finally, the cell response to SF/gelatin/rGO/DEX composite film was investigated. The results showed that the released DEX could interrupt astrocyte growth, reduce the inflammatory response and show not toxic to neurons, which exhibit the great potential for application of the e-SgG-D electrodes implanted in vivo.