title: Nitric oxide release from a single cell measured in situ by a porphyrinic-based microsensor.
abstract: Nitric oxide is an important bioregulatory molecule, being responsible, for example, for activity of endothelium-derived relaxing factor (EDRF). Acute hypertension, diabetes, ischaemia and atherosclerosis are associated with abnormalities of EDRF. Nitric oxide is thought to be a retrograde messenger in the central nervous system. The technology is not yet available for rapid detection of NO released by a single cell in the presence of oxygen and/or nitrite, so the release, distribution and reactivity of endogenous NO in biological systems cannot be analysed. Here we describe a porphyrinic microsensor that we have developed and applied to monitoring NO release in a microsystem. We selectively measured in situ the NO released from a single cell with a response time of less than 10 ms. The microsensor consists of p-type semiconducting polymeric porphyrin and a cationic exchanger (Nafion) deposited on a thermally sharpened carbon fibre with a tip diameter of approximately 0.5 microns. The microsensor, which can be operated in either the amperometric or voltammetric mode, is characterized by a linear response up to 300 microM and a detection limit of 10 nM. Nitric oxide at the level of 10(-20) mols can be detected in a single cell.
authors.affiliation: Department of Chemistry, Oakland University, Rochester, Michigan 48309-4401.
authors.forename: T
authors.initials: T
authors.lastname: Malinski
authors.forename: Z
authors.initials: Z
authors.lastname: Taha
mesh_terms: D000818:Animals; D015374:Biosensing Techniques; D002478:Cells, Cultured; D004730:Endothelium, Vascular / Q000378:metabolism*; D066298:In Vitro Techniques; D009569:Nitric Oxide / Q000032:analysis / Q000378:metabolism*; D011166:Porphyrins; D013552:Swine
chemical_list: D011166:Porphyrins; D009569:Nitric Oxide