Abstract
Purpose :
The photovoltaic-powered sub-retinal prosthesis with divisional-power-supply-scheme (DPSS) was designed to increase the power efficiency for each electrode by providing electricity to only a subset of electrodes at any moment in time with its total power. Although our previous studies have demonstrated its feasibility in eliciting spiking responses of retinal ganglion cells (RGCs) in wild type mice using multi-electrode array, the performance of the new generation of prosthetic chip with higher electrode density and much improved circuit needs to be assessed more systematically. This study was aimed to evaluate the efficacy of photovoltaic-powered prosthesis with DPSS in evoking responses of RGCs in rd1 mice in vitro.
Methods :
The 16x16 electrode array of photovoltaic-powered prosthesis with DPSS of 32 divisions was used to provide electrical stimulation from the sub-retinal side. The retina was placed RGC side up on the prosthetic chip. The spiking responses of RGCs from adult rd1 mice were measured by using the whole-cell current clamp recording. The targeted RGCs were labeled with Lucifer yellow.
Results :
The spiking responses of RGCs from adult rd1 mice were reliably evoked with electrical stimulation when the photovoltaic-powered sub-retinal prosthesis with DPSS was activated with the whole field light illumination. Although different types of RGCs had various levels of stimulation thresholds, the light intensity required for generating sufficient electrical current to evoke RGC responses was lower than the one used in our previous generations of retinal chips. In addition, the temporal resolution was set by the DPSS switch frequency and the spatial resolution was confined in its electrode and the immediate surround.
Conclusions :
Reliable activation of rd1 mouse RGCs by electrical stimulation in vitro using a photovoltaic-powered chip with DPSS demonstrates the feasibility of photovoltaic-powered sub-retinal prosthesis, and a wireless device to restore vision of the blind in the future.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.