MEASUREMENTS OF NITRIC-OXIDE IN BIOLOGICAL-MATERIALS USING A PORPHYRINIC MICROSENSOR

The application and optimization of a microsensor for in situ measurem ents of nitric oxide (NO) in biological systems are described. The sen sor (diameter 0.5-0.8 mum), exhibiting a response time better than 10 ms and a detection limit of 10 nM, consists of several layers of p-typ e semiconducting polymeric porphyrin and cation exchanger (Nafion) dep osited on a thermally-sharpened carbon fiber. The sensor has been appl ied to studies of NO release from a single endothelial cell in a pulmo nary artery, as well as for the determination of NO in blood.