Abstract: The inventive microsensor and method for regulating the sensitivity primarily aims at measuring the nitrate concentration in a surrounding medium by use of a concept named “Migrational Sensitivity Control” (MSC). The sensitivity of the sensor is regulated by impressing an electrical potential difference or an electrical current between a surrounding medium, e.g. waste water, containing a primary substance to be measured, and a substance chamber inside the microsensor. The microsensor contains bacteria which metabolizes the primary substance into a secondary substance, the concentration of which is proportional to the conentration of the primary substance to be measured. By measuring the concentration of the secondary substance the concentration of the first substance can be found. By varying the impressed voltage or current, the sensitivity of the microsensor can be controlled.

Abstract: A biosensor (1) includes a capillary (3) having a channel (30) with an inlet port (30a) for taking in a sample liquid, a membrane (8) for promoting the movement of the sample liquid through the channel (30), and a reaction part (7) containing a reagent that reacts with a component to be tested in the sample liquid whose movement has been promoted by the membrane (8).

Abstract: An electrochemical test device is provided for determining the presence or concentration of an analyte in an aqueous fluid sample. The electrochemical test device includes a working electrode and a counter electrode made of an amorphous semiconductor material. The working electrode is overlaid with a reagent capable of reacting with an analyte to produce a measurable change in potential which can be correlated to the concentration of the analyte in the fluid sample. The test device optionally contains a reference electrode made of an amorphous semiconductor material having a reference material on the reference electrode. The test device electrodes can be constructed on a flexible film substrate, such as a polymeric film or a metal foil coated with a non-conductive coating.

Abstract: The present invention includes a method and sensor that is easy to assemble and can operate to effectively detect an air borne or exogenously introduced analyte. In one embodiment, the assembled sensor includes a top cap capable of receiving a first electrolyte and a bottom cap capable of receiving a second electrolyte. The assembled sensor also includes a flexible boot that holds together the top cap, the bottom cap and a membrane. The membrane is located between the first electrolyte and the second electrolyte and enables an electrical device to detect an analyte (e.g., hazardous chemical) which originally entered the sensor through a passage in the top cap and interacted with the membrane.

Abstract: The present invention relates to a test strip and a biosensor having an increased conductivity and a slurry comprising a fiber, meal particles having a size in nanometer and a bioactive substance. The invention is characterized by incorporating metal particles having size in nanometer into the reaction layer of test strip and biosensor to increase the conductivity between the reaction layer and the electrodes so that the redox reaction can be readily completed and the measurement time can thus be shortened.

Abstract: The present invention is directed to the development of a biosensor based on the immuno-chromatographic method that can provide an assay speed and convenience required for point-of-care (the doctor's office and emergency room) testing or home-version diagnosis. Though certain physical symptoms, such as pregnancy and ovulation, or bacterial infection may be identified by a qualitative analysis for the presence of indicating substances, most analytes for clinical investigation demand their concentrations known in specimens. Therefore, the inventors of the present invention have developed a novel biosensor by combining the immuno-chromatographic method and the electric conductivity detection technology so that on-site quantitative determination at the points of care or at home may be carried out.

Abstract: The present invention provides a biosensor which enables quick measurement and is excellent in storage characteristic. This biosensor comprises an electrically insulating base plate on which an electrode system having at least a measuring electrode and a counter electrode is formed, a cover member which is integrated to the base plate so as to form a sample solution supply path for supplying a sample solution to the electrode system between the cover member and the base plate, and a carrier composed of fiber supporting a reagent containing at least an oxidoreductase, and the carrier is placed in the sample solution supply path. Preferably, the carrier is constituted at least of two carrier pieces and each carrier piece supports a different reagent.

Abstract: An L-phenylalanine sensor wherein all of the reagents required in determining L-phenylalanine are integrated together, thereby enabling quick and convenient quantification without resort to any special equipment, devices or techniques. This sensor is fabricated by integrating L-phenylalanine dehydrogenase, oxidized nicotinamide adenine dinucleotide (NAD+) or oxidized nicotinamide adenine dinucleotide phosphate (NADP+) as a coenzyme and an electron mediator, which are employed as reagents, with an electrode system comprising at least a working electrode and a counter electrode. Also, a method of determining L-phenylalanine which comprises adding a sample containing L-phenylalanine to the above-described sensor and electrochemically quantitating L-phenylalanine is provided.

Abstract: On an insulating substrate 1 is formed an electrode 2, on which is then formed a protection layer 3 consisting of a methacrylate-resin polyfluoroalcohol ester layer.

Abstract: A device for monitoring an analyte is described, which includes (a) a support having an interior surface and an exterior surface; (b) a substrate connected to the interior surface of the support; (c) a spacer connected to the interior surface of the support and encompassing the substrate; and (d) a first membrane, permeable to the analyte, having an interior surface and an exterior surface, the interior surface being connected to the spacer. A chamber that encloses the substrate is defined by the interior surface of the support, the spacer, and the interior surface of the first membrane. The spacer exceeds the substrate in elevation such that a void volume exists between the interior surface of the first membrane and the substrate. A method of using the device for the transdermal monitoring of an analyte is also described.

Abstract: An improved membrane based biosensor incorporates sensing and reference electrodes and a dc electrical potential produced by a counter electrode. The biosensor incorporates ionophores. The conductivity of the membrane is dependent on the presence or absence of an analyte. A functional reservoir exists between the sensing electrode and a lipid membrane deposited on the sensing electrode. The invention also includes the method of detecting the presence or absence of the analyte by use of the biosensor.

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: A device, for use in the electrochemical analysis of an analyte in a small volume liquid sample, having a non-conducting substrate (1); a conductive layer, deposited on the substrate, in two parts (2a, 2b), defining a non-conducting gap (8) therebetween; an analyte-specific reagent (5) coated on the conductive layer, on one side of the gap; a reference electrode (3) on the conductive layer, on the other side of the gap; a spacer layer (4) deposited over the conductive layer; a monofilament mesh (6) coated with a surfactant or chaotropic agent, the mesh being laid over the reagent, the reference electrode and the spacer layer; and a second non-conductive layer (7) adhered to the mesh layer, but not coextensive therewith, thereby providing a sample application area (9) on the mesh.