Hemispherical microelectrode array for retinal neural recording

In order to study the neuronal visual encoding process in the retina, ex-vivo animal experiments have been conducted using multi-electrode arrays (MEAs) capable of recording electrical signals from retinal tissues. In the conventional retinal experiments, it is inevitable to flatten the retinal tissue from its original hemispherical shape to form tight attachment to conventional planar electrode arrays or substrates. In the process of deforming the tissue, the retina is subject to mechanical stress, which may cause abnormal physiological reactions. To solve this problem, we present an innovative hemispherical MEAs with a curvature so that the retinal tissue can closely attach to the electrodes without deformation. The proposed MEAs is composed of non-toxic aluminum (A1) foil and elastomeric PDMS substrate. In addition, the fabrication is performed using a simple and inexpensive process. It is expected to stably record the retinal responses from multiple retinal ganglion cells around the optical disc because of the uniform adhesion while maintaining the original shape of the retina.