CMOS imager microsystem for multi-bacteria detection

The paper presents the design and implementation of a Complementary Metal-Oxide Semiconductor (CMOS) based imaging microsystem that can monitor multiple bacteria and viruses simultaneously. The sensor microsystem uses bacteriophages or phage organisms as recognition elements to detect deadly bacteria such as Anthrax, Salmonella, and E-Coli. The genetically engineered phages are viruses that recognize specific receptors on the bacteria surface to which they bind with extreme selectivity and sensitivity. The phages are tagged with fluorophores to render them optically responsive and are immobilized on the surface of an addressable micro-LED array. The LEDs are used to excite the phage organisms and subsequently the phages fluoresce. The intensity of the fluorescence is dependent on the concentration of specific bacteria attached to the phages and is detected by a custom- designed CMOS imager. The imager has a 26times20 phototransistor pixel array and is designed using AMIS 1.5 mum technology. Each photo-pixel is designed to achieve a sensitivity of 24 mV/nA with a maximum imager acquisition rate of 1000 frames/sec operating on a 5 V DC supply.