In vitro Biocompatibility of a Platinum-Electrode Embedded Photosensitive Polyimide (Durimide) Retinal Prosthesis

Abstract

Purpose: The photosensitive polyimide film, Durimide, is a common component of retinal prostheses; however, retinal cell response to Durimide has not been effectively studied This work assessed the in vitro biocompatibility of a retinal prosthesis containing platinum-electrode embedded Durimide film.Materials and methods: Biocompatibility evaluation assessed cytotoxicity, attachment, and proliferation of two cell lines: a human retinal pigmented epithelium cell line (CRL) and a rhesus monkey choroid- retinal endothelial cell line (RF/6A). Cells were cultured with the platinum-electrode embedded Durimide film, with tissue-culture treated polystyrene plates (TCPS) used as a control substrate for cell growth. The effect of a Durimide-exposed medium on cell apoptosis and life cycle was assessed using flow cytometry (FCM).Results: The indirect cytotoxicity evaluation revealed no toxic effect of the prosthesis on cells. The attachment and proliferation of CRL and RF/6A cells cultured with the Durimide prostheses showed no significant differences to the control. The FCM experiments demonstrated a liquid medium exposed to the prosthesis had no effects on apoptosis or cell life cycle in comparison with the control (p > 0.05).Conclusions: The results demonstrate that Durimide has good biocompatibility with retinal cell lines CRL and RF/6A. In conclusion, while further in vitro and in vivo studies are required to clarify long-term effects, Durimide is indicated as a promising material with suitable biocompatibility for retinal implants.