Biomolecular image sensor of bacteriorhodopsin patterned by electrodeposition

In this paper, we report a biomolecular image sensor using a retinal membrane protein ´bacteriorhodopsin (bR). Characteristics of the bR photoreceptor, which was fabricated by our process, were measured. bR pumps protons from the intracellular side to the extra-cellular side by light irradiation. The sandwiched structure ITO/bR/KCl/Au generates charges proportional to the light intensity. The structure can be used as a photoreceptor by measuring the photoelectric response with a charge amplifier. To fabricate the photoreceptor array, a bR patterning method with electro-deposition and hydrophilic and hydrophobic surface modification was developed. An image sensor, which consists of an 8×8 array of 1-millimeter square bR photoreceptors, was fabricated. It was demonstrated that the image sensor could detect a gradual image and black and white images.