Biophotoreceptor Arrays

Abstract

Biophotoreceptor arrays are hybrid electronic devices that utilize spectrally sensitive neuronal cells and biomolecules as the primary photon‐detecting element in a distributed network of light sensors. The patterned microelectrode arrays that interface with the biological material are constructed from readily available silicon‐based circuitry or, more recently, electrodes imprinted on flexible polymer substrates. From an engineer's perspective, these biological materials present new design opportunities for developing imaging systems that more closely emulate the signal detection and information processing structures found in nature. Several important attributes of natural vision include highly sensitive light receptors based on molecular phototransduction, a nonregular distribution of sensing elements on the imaging surface, and nonplanar image formation in the eye. The primate retina is one illustrative example of how phototransduction and neuronal interactions can lead to efficient imaging of dynamic three‐dimensional environments. The extraction and deposition of nerve cells and molecular proteins on microelectrode array platforms provide researchers with a means to observe the behavior of these distributed sensing systems. Organic and flexible polymer electronics represent a new technology that permit the creation of nonrigid photoreceptor arrays which replicate the curved imaging surfaces of single aperture and apposition compound eyes. A simple motion detection system is presented as an illustration of how photosensitive biomaterials and flexible printed electronics provide an alternative paradigm for developing new types of imaging systems. An important area where biomedical researchers can exploit engineered biophotoreceptor arrays is the fabrication of biocompatible artificial retinas and prosthetic devices for patients with severe visual impairment.