Fabrication and in vitro Biocompatibility of Flexible Polyimide-Based Microelectrode Array for Visual Prosthesis

Purpose: To make sure the biocompatibility and to get the permission to use the EPIRET3-device in a clinical trial according to German laws and to European ISO standards. To characterize the systems and the interaction with the retinal cells of RP-subjects after explantation. Methods: We tested the finally designed wireless epiretinal implants preclinically in vitro. The systems were directly seeded with murine L929 fibroblast cells. Stainings for testing the integrity of the cell membranes were perfomed. Indirect tests were used to detect potentially toxical substances in the cell suspension. After implantation in 6 RP-subjects, the system remained for 28 days. Explantation was done, and the electrode devices were characterized using scanning electron microscopy (SEM/REM). Results: The finally designed systems showed no signs of toxicity in the direct cell tests and in the indirect tests of the cell suspension. After implantation, remaining and explantation of the systems we found small groups of retinal cells on the epiretinally located electrode device. The cells were mostly identified as retinal glial (Muller) cells. Conclusions: The EPIRET3-System is a biocompatible and safe retinal implant system, successfully implanted in RP-individuals, and explanted after 28 days. The short-term biocompatibility in RP-subjects was shown in our project, following studies should characterize the long-term biocompatibility of the implants. CR: B. Sellhaus, None; T. Schanze, None. Support: BMBF, Germany CT: DE/CA21/A/07/Dr.Schmidt IOL/EPI-RETIII 3010 D606 Fabrication and in vitro Biocompatibility of Flexible Polyimide-Based Microelectrode Array for Visual Prosthesis