Development of an optogenetic triggered biohybrid cochlea implant

Optical stimulation of excitable cells can provide superior spatial resolution and selectivity compared to electrical stimulation. However, stimulation by means of optoacoustics was shown to be ineffective in deaf animals. Optogenetics offers a promising solution by permitting minimally invasive, genetically targeted and precise photostimulation. This work aims to develop a biohybrid implant consisting of an artificial network of optogenetic modified neurons embedded in a biocompatible hydrogel. To trigger resident spiral ganglion neurons in the cochlear, the implant comes along with a light-conducting fiber. As a first proof of concept, two optogenetic channels, Chronos and Channelrhodopsin-2 (ChR2), were transfected into N2A cells. Upon blue light illumination, cells responded with an inward current. Next, two groups of neurons, one transduced with ChR2 or Chronos and one control group, will be spatially separated, but still can form connections. Following, light will be applied on transduced cells and the propagation of the signal will be measured. The proposed principle would allow to apply the advantages of optogenetics in an implant without presupposing in vivo gene therapy.