Telesensor integrated circuits.

Progress in personal computing has recently permitted small research programs to design and simulate application-specific integrated circuits (ASICs). Inexpensive fabrication of silicon chips can then be obtained using chip foundries, and quite complex circuits can be greatly reduced in size with an accompanying increase in certain performance characteristics. Within the past 5 years it has also become possible to design ASICs which can transmit and receive radio signals and which thus may be employed in applications in which wired connections for input and output of signals are not practicable. We are currently developing research-grade prototype ASICs for the monitoring of human vital signs. In this case one or more sensors placed on an ASIC provides a signal to be transmitted a distance of 2-3 meters to a receiver/display unit. The use of ASIC telesensors provides the possibility of wireless monitoring, including long-term monitoring, with inexpensive and unencumbering devices. Their self-contained nature permits a number of potential uses in future biomedical applications as new sensors are devised which are amenable to deployment on silicon.

DNA biochip using a phototransistor integrated circuit.

This work describes the development of an integrated biosensor based on phototransistor integrated circuits (IC) for use in medical detection, DNA diagnostics, and gene mapping. The evaluation of various system components developed for an integrated biosensor microchip is discussed. Methods to develop a microarray of DNA probes on nitrocellulose substrate are discussed. The biochip device has sensors, amplifiers, discriminators, and logic circuitry on board. Integration of light-emitting diodes into the device is also possible. To achieve improved sensitivity, we have designed an IC system having each phototransistor sensing element composed of 220 phototransistor cells connected in parallel. Measurements of fluorescent-labeled DNA probe microarrays 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.