Monolithically Integrated Flexible Artificial Retina Microsystems Technology and in vitro Characterization

Abstract

 

Purpose:

 

To extend previous technologies available for artificial retinaimplementation to monolithically integrate electronics togetherwith photo detectors and the micro electrode array all in abiocompatible and flexible format.

 

Methods:

 

Develop a flexible technology capable of integrating photo detectors,micro electrodes and electronics using CMOS technology. Theflexible format allows better proximity between electrodes andretina neurons for local stimulation, and the integrated localelectronics allows supplying individual electrode the adequateand appropriate stimulation waveforms right next to each individualelectrodes. Use in vitro techniques on device for initial assessments.

 

Results:

 

We successfully implemented a 64-element micro electrode arrayand a flexible 1,024-element artificial retina with 30 µmpitch (Fig. 1(a)) using this flexible technology. The lattersenses local light intensity and generate corresponding biphasiccurrent at each pixel (Fig. 1(b)). We use loose patch and whole-cellpatch clamp techniques in vitro to characterize the retinalganglion cell responses on these arrays Fig. 2.

 

Conclusions:

 

This work demonstrates the feasibility to monolithically integrateelectronics using 180 nm CMOS transistors together with photodetectors and the micro electrode array all in a biocompatibleand flexible format with the total thickness of the microsystemaround 30 µm. Excitation of retina ganglion cells is demonstratedin vitro.  

 

 

Keywords: retina • ganglion cells • electrophysiology: non-clinical