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.

Real-time electrical detection of nitric oxide in biological systems with sub-nanomolar sensitivity

“…The production of NO by vascular ECs has an important role in normal vascular physiology [50][51][52] . Endothelial-derived NO can account for inhibition of platelet aggregation and adhesion and for the modulation of vascular tone.…”

Nitric oxide in brain: diffusion, targets and concentration dynamics in hippocampal subregions

“…Later, Shibuki's probe enabled WPI (Sarasota, USA) to develop the first widely commercially available nitric oxide sensor, the ISO-NO. A second hallmark in the development of microsensors was the introduction of catalytic electrode surfaces by Malinski and Taha (1992), who used a carbon fiber electrode modified by the electropolymerization of Ni(II)-porphyrin. Following this advance, the deposition of polymeric films that catalyse NO Å oxidation at the electrode surface became an attractive approach and several materials have been proposed, including different types of metalloporphyrins, metallophtalocyanines, copper-platinum microparticles, palladium and iridium oxide (Bedioui and Villeneuve, 2003).…”

Surface modification of a perfluorinated ionomer using a glow discharge deposition method to control protein adsorption

“…The commercially available polymer Nafion ™ (Dupont Chemical), has been used in various types of biosensors, including nitric oxide sensors [8][9][10][11][12][13][14][15] as well as glucose/oxygen sensors [16,17]. For a glucose biosensor, Nafion serves four purposes, namely: a) to reject large, negative molecules [18], b) to physically protect the glucose oxidase enzyme that drives the chemical reaction of the biosensor (acting as a physical barrier), c) to act as a glucose transportlimiting membrane, thereby reducing the oxygen requirement of the biosensor and d) to maintain some level of biocompatibility, especially after curing of the Nafion membrane [19].…”