In recent years, microsensors (5-30 microns in diameter) have been developed to investigate rapid (11000 Hz) chemical signaling in biological systems. Recent electrochemical recording methods such as highspeed chronoamperometry (1-25Hz), fast-scan cyclic voltammetry (10 Hz and 100-1000 v/sec scan rates) and amperometry (1000 Hz resolution) have been developed for such recordings. The study of rapid chemical signaling requires the use of microelectrodes that are coupled to sensitive instrumentation that is capable of recording and converting the small changes in current that are due to chemical reactions at the surfaces of the microsensors. A few laboratory designed instruments and some commercial instruments are available. However, no low noise "turnkey" system that is capable of recording, displaying, analyzing data and outputting results is available to the scientific community. In addition, some commercial instrumentation often requires a combination of other laboratory instruments as seen in Figure la (adapted from Stamford et al. 1992). Presently, there is no self contained microcomputer-based instrument that is available to scientists that encompasses the capabilities to record rapid electrochemical signals using fast-scan cyclic voltammetry, highspeed chronoamperometry, 1000-6000Hz amperometry, more standard electrochemical methods, and new modifications of the rapid electrochemical recording methods. A major goal of this proposal is to carry out the Phase I (design) and Phase II (modification and refinement) development of an automated multi-channel recording system as depicted in Figure lb. Such an instrument, which we call FAST for Fast Analytical Sensing Technology, will be useful to students, postdoctoral fellows and principal investigators in the fields of cell biology, chemistry, biology, neuroscience, pharmacolog y, physiology, chemoreception, marine biollogy, psychology and other biological sciences. The second goal of this proposal is to further develop microsensors for the selective, rapid, and sensitive measures of dopamine, norepinephrine, serotonin, nitric oxide and glutamate in biological systems. Both carbon fiber based probes and semiconductor based probe designs will be developed. Further sensor development is needed to enhance the recording capabilities of currently available instrumentation and the proposed FASTin vivo electrochemical recording system. ~
