Abstract: Biocompatible polymeric materials capable of providing in situ release of nitric oxide (NO) included diazeniumdiolated fumed silica as a filler in a multilayer polymer structure to release NO upon contact with water (blood). The blood-contacting polymer surface is preferably multi-layered so that the NO-releasing layer, containing the diazeniumdiolated fumed silica, is shielded from blood contact by one or more top (or base) coats. When in contact with blood, the NO released at the surface of the polymer prevents platelet activation and adhesion to the surface, thereby reducing platelet consumption, risk of thrombus formation and other clinical complications associated with interactions between blood and foreign materials.

Abstract: A material includes a surface and a reactive agent that is located at the surface of the material, covalently attached to a backbone of the material, and/or located within the material. The reactive agent has nitrite reductase activity, nitrate reductase activity, and/or nitrosothiol reductase activity. The reactive agent also converts at least one of nitrites, nitrates and nitrosothiols to nitric oxide when in contact with blood. A reproducible nitrosothiol sensor is also disclosed.

Abstract: A method and apparatus for non-invasively determining the concentration of a substance in blood, such as glucose, include a sample portion arranged for contacting an eye region of a user to obtain a tear fluid sample, a sensor in communication with the sample portion for generating a signal related to the tear substance concentration, and a processor in communication with the sensor for determining a blood substance concentration corresponding to the tear substance concentration.

Abstract: A rotating electrode configuration lowers the detection limits of polyion-sensitive membrane electrodes. Planar potentiometric polycation and polyanion-sensitive membrane electrodes were prepared by incorporating tridodecylmethylammonium chloride and calcium dinonylnaphthalene sulfonate, respectively, into plasticized PVC or polyurethane membranes, and mounting discs of such films on an electrode body housed in a rotating disk electrode apparatus of the type used in voltammetry. Due to the unique non-equilibrium response mechanism of such sensors, rotation of the polyion-sensitive membrane electrodes at 5000 rpm resulted in an enhancement in the detection limits toward heparin (polyanion) and protamine (polycation) of at least 1 order of magnitude (to 0.01 U/ml for heparin; 0.02 &mgr;g/ml for protamine) over that observed when the EMF responses of the same electrodes were assessed using a stir-bar to achieve connective mass transport.

Abstract: Biocompatible materials that have the ability to release nitric oxide (NO) in situ at the surface-blood interface when in contact with blood. The materials which may be polymers (e.g., polyurethane, poly(vinyl chloride), silicone rubbers), metals, such as stainless steel, carbon, and the like are provided with biocatalysts or biomimetic catalysts on their surface that have nitrite, nitrate and/or nitrosothiol-reducing capability that. Illustratively, the catalysts are adsorbed or immobilized at the surface of the material. The catalysts can act on endogenous nitrite/nitrate or nitrosothiols within the blood creating a local increase in the NO levels at the surface of the material. An illustrative enzymatic biocatalyst is mammalian xanthine oxidase. In another illustrative embodiment, a biomimetic catalyst is a copper (Cu(II)-ligands complex, e.g., dibenzo[e,k]-2,3,8,9-tetraphenyl-1,4,7,10-tetraaza-cyclododeca-1,3,7,9-tetraene. In some cases, lipophilic salts of nitrite/nitrate (e.g.

Abstract: An enzyme sandwich immunoassay, device and cassette therefor for determining a target analyte are described. The enzyme sandwich immunoassay cassette (B) comprises a microporous membrane support (m) having coated thereon a conductive metal layer overlaid with a capture antibody layer (e).

Abstract: A novel enzyme sandwich immunoassay cassette comprising a microporous membrane support having coated thereon:(a) a conductive metal layer; and(b) a capture antibody layer over the conductive metal layer.

Abstract: A polymeric membrane electrode gives potentiometric responses to macromolles, such as protamine, in solution or biological specimens. A protamine-responsive membrane includes a lipophilic cation-exchange material for ionic macromolecules in a specially formulated plasticized, polymeric matrix material. Potentiometric response to protamine has been observed in membranes comprising 30-70 wt. % polymeric matrix material, such as polyvinyl chloride; 1-3 wt. % salt of a tetraphenylborate, such as potassium tetrakis(4-chlorophenyl) borate or salt of an organophosph(on)ate, such as calcium bis-[4-(1,1,3,3-tetramethylbutyl)phenyl] phosphate; and 30-70 wt. % of a plasticizer, such as 2-nitrophenyl octyl ether or tris (2-ethylhexyl) phosphate.

Abstract: An anion exchange membrane for ionic macromolecules, specifically heparin, which is formed of a polymeric matrix material and an anion exchange material suitable for heparin detection can be employed in an electrochemical sensor arrangement to directly measure the concentration of heparin ions in blood or blood fluid. Potentiometric response to heparin has been observed with membranes comprising 30-70 wt. % polymeric matrix material, such as polyvinyl chloride, 0.1-12 wt. % quaternary ammonium salt, such as tridodecyl methyl ammonium chloride, and 30-70 wt. % of a plasticizer, such as dioctyl sebacate. Moreover, a solid state sensor employs tridodecyl methyl ammonium chloride (TDMAC) dissolved in a polymeric compound, such as silicone rubber, to form a membrane which is responsive to heparin concentration.

Abstract: An anion exchange membrane for ionic macromolecules, specifically heparin, which is formed of a polymeric matrix material, an anion exchange material suitable for heparin detection, and a plasticizer can be employed in an electrochemical sensor arrangement to directly measure the concentration of heparin ions in blood or blood fluid. Potentiometric response to heparin has been observed with membranes comprising 30-70 wt. % polymeric matrix material, such as polyvinyl chloride, 0.1-12 wt. % quaternary ammonium salt, such as tridodecyl methyl ammonium chloride, and 30-70 wt. % of a plasticizer, such as dioctyl sebacate.

Abstract: A dual lumen CO.sub.2 catheter is formed of medical grade dual lumen silicone rubber tubing which has been impregnated with tridodecyl amine. The silicone tubing is gas permeable, and an external reference electrode is used to monitor the potential across the impregnated outer wall of the dual lumen tubing as a function of pH. The analyte to be monitored is selected from the group consisting of CO.sub.2, NH.sub.3, SO.sub.2, NO.sub.2, H.sub.2 S, and HCN, the internal reference and electrolyte solutions contained in the lumens being selected in response to the particular analyte desired to be monitored. In a CO.sub.2 embodiment, the reference lumen is filled with a buffered internal reference solution, and the response lumen is filled with a bicarbonate filling solution. Reference wires formed of Ag/AgCl in respective ones of the lumens forms the internal electrodes.

Abstract: A simplified gas sensor which includes a pH sensitive transducer having a gate-insulated field effect transistor (FET) structure. The gas sensor is particularly adapted to detect carbon dioxide in fluids.

Abstract: A bio-selective potentiometric electrode probe for the determination of amino acid concentrations in aqueous liquids comprising an ammonia gas analytical electrode provided at its tip with a closely adjacent thin layer of a fresh animal tissue containing, as a natural constituent thereof, an enzyme effective to catalyze degradation of the specific amino acid in analysis to either ammonia or to an intermediate compound subject to further degradation to ammonia by an additional enzyme, which ammonia is a function of the amino acid concentration in the liquid.