DNA biochip using a phototransistor integrated circuit

This work describes the development of an integrated biosensor based on pho totransistor integrated circuits (IC) for use in medical detection, DNA dia gnostics, and gene mapping. The evaluation of various system components dev eloped for an integrated biosensor microchip is discussed. Methods to devel op a microarray of DNA probes on nitrocellulose substrate are discussed. Th e biochip device has sensors, amplifiers, discriminators, and logic circuit ry on board. Integration of light-emitting diodes into the device is also p ossible. To achieve improved sensitivity, we have designed an IC system hav ing each phototransistor sensing element composed of 220 phototransistor ce lls connected in parallel. Measurements of fluorescent-labeled DNA probe mi croarrays and hybridization experiments with a sequence-specific DNA probe for the human immunodeficiency virus 1 system on nitrocellulose substrates illustrate the usefulness and potential of the DNA biochip.