A CMOS image sensor with optical and potential dual imaging function for on-chip bioscientific applications

An optical and potential dual imaging CMOS sensor for bioscientific applications was proposed and fabricated. The CMOS image sensor has the capability to simultaneously capture optical and on-chip potential images. The sensor is designed with target applications of on-chip DNA (or protein) microarray analysis and on-chip neural imaging. A potential imaging function was implemented onto a CMOS image sensor with a simple pixel circuitry that is compatible with optical image sensor pixels. The basic properties of the potential-sensing pixel were characterized. By choosing an appropriate operating sequence and off-chip configuration, the sensor can be operated in either a wide-range potential imaging mode (>5 V) or a high-resolution potential imaging mode (1.6 mV). The sensor is applicable for most of the target applications and is capable of detecting a pH change in the solution placed on the surface. Two-dimensional optical and potential dual imaging was successfully demonstrated, and the profile of a potential spot smaller than 50 μm was clearly observed.