Multimembrane Carbon Fiber Electrodes for Physiological Measurements of Nitric Oxide

Abstract

Carbon fiber electrodes were chemically modified with polymeric membranes of nickel porphyrin, Nafion, immobilized ascorbic acid oxidase and either polylysine or polypyridinium to provide selectivity of anodic detection of nitric oxide (NO) in physiological systems. These composite electrodes were demonstrated to preclude interference by physiological concentrations of electroactive species and by L-arginine (L-Arg), N-nitro-L-arginine methyl ester (L-NAME) and carbon monoxide (CO). The composite electrode response time was 500 ms and the chronocoulometric detection limit was 0.5 nM NO. In situ measurement of NO was demonstrated in brain slices in vitro and in the anesthetized brain in vivo with detection limits of 8 and 173 nM NO in these tissue preparations, respectively.