The design and preparation of a flexible bio-chip for use as a visual prosthesis, and evaluation of its biological features

We aimed to design and manufacture a novel low-cost polyimide microelectrode array (MEA) chip for visual prosthesis research and to evaluate its biological features. A microelectrode array was developed, based on Flexible Printed Circuit Board (FPC) technology which enables electrical stimulation of the cortex. In an in vitro experiment, rat visual cortex cells were co-cultured with the chip and examined using scanning electron microscopy. Trypan blue exclusion and methyl blue tetrazolium tests showed that cell viability and survival rates (90–98%) did not significantly differ between the co-cultured chip group and the control group. In an in vivo experiment HE/Nissl staining performed to investigate the possibility of brain tissue degeneration around implanted MEAs showed no negative effects of the chip on visual cortical cells after 1 month in situ. The good functional characteristics and biocomptability suggest that such a low-cost device could have widespread application, particularly in countries with a large blind population and limited financial resources