Planar nitric oxide (NO)-selective ultramicroelectrode sensor for measuring localized NO surface concentrations at xerogel microarrays.

A planar ultramicroelectrode nitric oxide (NO) sensor was fabricated to measure the local NO surface concentrations from NO-releasing microarrays of varying geometries. The sensor consisted of platinized Pt (25 microm) working electrode and a silver paint reference electrode coated with a thin silicone rubber gas permeable membrane. An internal hydrogel layer separated the Pt working electrode and gas permeable membrane.

Miniaturized glucose biosensor modified with a nitric oxide-releasing xerogel microarray.

An enzyme-based glucose biosensor modified to release nitric oxide (NO) via a xerogel microarray is reported. The biosensor design is as follows: (1) glucose oxidase (GOx) is immobilized in a methyltrimethoxysilane (MTMOS) xerogel layer; (2) a blended polyurethane/hydrophilic polyurethane coating prevents enzyme leaching and imparts selectivity for glucose; and (3) micropatterned xerogel lines (5 microm wide) separated by distances of 5 or 20 microm provide NO-release capability. This configuration allows for increased glucose sensitivity relative to sensors modified with NO-releasing xerogel films since significant portions of the sensor surface remain unmodified.

Direct detection of S-nitrosothiols using planar amperometric nitric oxide sensor modified with polymeric films containing catalytic copper species.

The direct amperometric detection of S-nitrosothiol species (RSNOs) is realized by modifying a previously reported amperometric nitric oxide gas sensor with thin hydrophilic polyurethane films containing catalytic Cu(II)/(I) sites. Catalytic Cu(II)/(I)-mediated decomposition of S-nitrosothiols generates NO(g) in the thin polymeric film at the distal tip of the NO sensor. Three different species are examined to create the catalytic layer: (1) a lipophilic Cu(II)-ligand complex; (2) Cu(II)-phosphate salt; and (3) small (3-microm) metallic Cu(0) particles.

Improved planar amperometric nitric oxide sensor based on platinized platinum anode. 1. Experimental results and theory when applied for monitoring NO release from diazeniumdiolate-doped polymeric films.

An improved miniature amperometric nitric oxide sensor design with a planar sensing tip (ranging from 150 microm to 2 mm in diameter) is reported. The sensor is fabricated using a platinized platinum anode and a Ag/AgCl cathode housed behind a microporous poly(tetrafluoroethylene) (PTFE; Gore-tex) gas-permeable membrane. Platinization of the working platinum electrode surface dramatically improves the analytical performance of the sensor by providing approximately 10-fold higher sensitivity (0.

Catalytic generation of nitric oxide from nitrite at the interface of polymeric films doped with lipophilic CuII-complex: a potential route to the preparation of thromboresistant coatings.

A novel approach potentially useful for the development of more thromboresistant polymeric materials is examined. The method is based on the catalytic generation of nitric oxide (NO) via Cu(I) mediated reduction of nitrite ions. Preliminary solution phase studies demonstrate that ascorbate or thiolate anions can generate Cu(I) from Cu(II) with subsequent catalytic conversion of any nitrite ions present to NO by the unstable Cu(I) species.

Spontaneous catalytic generation of nitric oxide from S-nitrosothiols at the surface of polymer films doped with lipophilic copperII complex.

A new approach for preparing potentially more blood-compatible nitric oxide (NO)-generating polymeric materials is described. The method involves creating polymeric films that have catalytic sites within (lipophilic copper(II) complex) that are capable of converting endogenous S-nitrosothiols present in blood (S-nitrosoglutathione (GSNO), S-nitrosocysteine (CysNO), etc.) to NO.