Micro-ring disc ultramicroelectrodes array for direct detection of NO-release from S-nitrosoglutathione

In this work, we report on the design, microfabrication and use of a ring disk ultramicroelectrodes array (RD-UMEs) for direct detection of nitric oxide (NO)-release from decomposition of S-Nitrosoglutathione (GSNO) catalyzed by copper species. The electrochemical device includes seven individually addressable sets of gold RD-UMEs pairs and four gold counter electrodes. For each pair of RD-UMEs, the gold ring is electrochemically modified by poly(eugenol)/poly(phenol) layers to act as NO-sensor while the gold disc electrode is electrochemically coated by a copper layer serving as Cu(2+) source for the catalysis of the in situ decomposition of GSNO. The mediated decomposition of GSNO by Cu(2+) is achieved in presence of ascorbate. NO released from GSNO is detected on NO ring electrode at the same potential applied to form the Cu(2+)-based catalyst (+0.8 V vs. Ag/AgCl) in phosphate buffer solution with or without serum. (C) 2011 Elsevier B.V. All rights reserved.