Abstract: A cholesterol sensor facilitating rapid measurement of serum cholesterol levels is disclosed. The sensor comprises an electrode system composed of at least a measuring electrode and a counter electrode and disposed on an electrically insulating base plate and a reaction layer formed on or in the vicinity of the electrode system. The reaction layer contains cholesterol esterase for catalyzing the conversion of cholesterol ester into cholesterol, cholesterol oxidase and a surfactant.

Abstract: Disclosed is an electrode probe and a body fluid examination equipment enabling examination of a trace amount of body fluid. The electrode probe comprises an insulating needle member, a working electrode lead disposed in the needle member, a working electrode whose lead is protruding outside from the needle member, a counter electrode disposed on the surface of the needle member, a lead connected to the counter electrode, and a reagent layer disposed in contact with or in the vicinity of the working and counter electrodes of the electrode system. When a trace amount of body fluid leaking on the skin surface is brought into contact with the reagent layer, the reagent layer dissolves which results in electron transfer whereby information about the concentration of analyte in the body fluid can be obtained from the electrode system.

Abstract: Disclosed is a biosensor facilitating high accuracy quantification of a specific component in a sample solution with no adverse influence of solid substances. The biosensor comprises an electrically insulating base plate, an electrode system comprising a working electrode and a counter electrode formed on the base plate, a reaction layer containing at least one enzyme disposed on the electrode system, and an anionic filter formed on the reaction layer for inhibiting permeation of solid components.

Abstract: A cholesterol sensor is disclosed which comprises an electrode system having a measuring electrode and a counter electrode formed on an electrically insulating base plate, an electrode coating layer for covering the electrode system and a reaction reagent layer formed on or in the vicinity of the electrode coating layer, wherein the reaction reagent layer comprises at least an enzyme for catalyzing cholesterol oxidation, an enzyme having a cholesterol ester hydrolyzing activity and a surfactant, the electrode coating layer comprises at least one selected from the group consisting of water-soluble cellulose derivatives and saccharides and is contained at such a concentration that imparts sufficient viscosity to a sample solution for enabling it to hinder invasion of said surfactant into said electrode system when said electrode coating layer is dissolved in said sample solution supplied to said sensor.

Abstract: The present invention provides a stable and cost-effective biosensor. The biosensor includes an electrically insulating base plate, an electrode system that includes at least a working electrode and counter electrode formed on the base plate, a reaction layer containing at least an enzyme, an electron acceptor that is formed on, or in the vicinity of, the electrode system, and a divalent water-soluble metallic salt provided in, or in the vicinity of, the reaction layer.

Abstract: The present invention provides a measurement device facilitating accurate quantitation of a substrate from a trace amount of sample and a highly reliable quantitating method of a substrate. The method uses an analysis element comprising a pair of electrodes for electrochemically quantitating reaction between a substrate in a sample and an oxidoreductase. One of the electrodes of the analysis element is a membrane formed on an inner wall of a cylindrical hollow space having an opening and the other is a needle. The needle electrode is projected temporarily external to the hollow space to puncture a subject and the resultant sample is collected from the subject.

Abstract: The present invention provides a method for quantifying a substrate having improved measurement accuracy and measurement sensitivity. According to the method for quantifying the substrate of the present invention, a constant voltage is applied to an electrode system, between a working electrode and a counter electrode, via a resistor connected in series with the electrode system after placing a sample solution containing the substrate on the electrode system, so as to oxidize an electron acceptor, which has been reduced by an enzyme reaction of the substrate, thereby determining a concentration of the substrate included in the sample solution based on an oxidizing current flowing in the course of oxidation.

Abstract: The biosensor of the present invention has a reaction layer that contains at least an oxidoreductase and an electron acceptor and is formed on an electrode system including a working electrode and a counter electrode on a base plate. The working electrode, the counter electrode, and lead conductors connecting with these electrodes are made of carbon. The counter electrode is formed in a substantially C shape, and the working electrode is arranged in a recess of the substantially C-shaped counter electrode. An insulating layer surrounds the counter electrode and the working electrode. A cover member with a groove is combined with the base plate to define a sample supply channel that is formed therebetween and runs toward the electrode system. The groove extends from one end of the base plate and passes over the electrode system, and the insulating layer extends to an air hole formed in a terminal of the groove of the cover member.

Abstract: Disclosed is a high performance biosensor free from the effect of any components existing in a sample solution other than a substrate. The biosensor comprises an electrically insulating base plate, an electrode system including a working electrode and a counter electrode provided on the base plate, and a reaction layer containing a hydrophilic polymer, an enzyme and an electron acceptor located over the electrode system. The reaction layer contains an excess amount of hydrophilic polymer in a range of 150 to 1,000% by weight of the enzyme.

Abstract: A biosensor includes: an insulating substrate; an electrode system formed on the insulating substrate which has a working electrode and a counter electrode; and a reaction layer formed on the insulating substrate which contains an oxidoreductase and an electron acceptor. The electron acceptor is ferricinium ion derived from ferrocene electrolyte.

Abstract: A biosensor is disclosed for application to a method for quantitative measurement of a substrate comprising a first step of causing a substrate contained in a sample to react with an oxidoreductase specific to the substrate in the presence of an electron mediator in oxidized state, a second step of applying a potential to a working electrode for reducing the electron mediator in oxidized state that remains not reduced in the first step, and a third step of measuring a reduction current flowing across the working electrode and a counter electrode. The biosensor comprises an electrically insulating base plate, an electrode system having a working electrode and a counter electrode formed on the base plate, and a reaction layer which is formed on or in the vicinity of the electrode system and contains at least an oxidoreductase and an electron mediator, the counter electrode including at least a reductant of a redox compound or an electrolytically oxidizable metal.

Abstract: There is disclosed an aqueous dispersed solution as a standard solution for determining lipid levels, having a dispersion form and a particle size, which are similar to those of serum lipids. A lipid-dispersed solution is obtained by evaporating an organic solvent from a mixture prepared by adding cholesterol, a phospholipid, a bile acid or bile acid salt, and a neutral lipid and/or a cholesterol ester in the organic solvent, swelling the resultant thin-film like mixture with water or buffer heated at a temperature higher than a phase transition temperature of the lecithin, and then dispersing the solution by a physical shear force. There can be easily obtained a solution having a cholesterol concentration of about less than 1,000 mg/dl, which is extremely stable and can be stored for a long period of time.

Abstract: A biosensor for rapid quantification of a specific component contained in various biological samples with high accuracy has an electrically insulating base, an electrode system including a working electrode and a counter electrode formed on one face of the insulating base, and a reaction layer formed on the insulating base in close contact with the electrode system. The reaction layer contains at least a hydrophilic polymer, a buffer and an enzyme which is separated from the buffer.

Abstract: The biosensor of this invention includes an electrically insulating substrate; an electrode system formed on the substrate which includes a working electrode and a counter electrode; and a reaction layer formed on the substrate or above the substrate with a space therebetween. The reaction layer includes a pyranose-oxidizing enzyme.

Abstract: The biosensor of this invention can quantify a substrate in a sample liquid by electrochemically measuring the amount of an electron acceptor that has been reduced by electrons generated in a reaction between the substrate and an oxidoreductase. The biosensor has an electrically insulating substrate and an electrode system formed on the substrate including a working electrode, a counter electrode and a third electrode used for detecting a liquid junction. The third electrode can be used merely for detecting a liquid junction, or can be used as both a reference electrode and a liquid junction detecting electrode.

Abstract: The biosensor of this invention can quantify a substrate in a sample liquid by electrochemically measuring the amount of an electron acceptor that has been reduced by electrons generated in a reaction between the substrate and an oxidoreductase. The biosensor has an electrically insulating substrate and an electrode system formed on the substrate including a working electrode, a counter electrode and a third electrode used for detecting a liquid junction. The third electrode can be used merely for detecting a liquid junction, or can be used as both a reference electrode and a liquid junction detecting electrode.

Abstract: A biosensor for quantification of a specific component contained in various biological samples comprises an electrically insulating base plate, an electrode system including a working electrode and a counter electrode which are provided on the electrically insulating base plate, a reaction layer formed on the electrode system including at least an oxido-reductase, and an enclosure member having a hollow space constituting a sample supplying channel on the electrically insulating base plate, wherein substantially the whole of the reaction layer is exposed to the hollow space.

Abstract: A biosensor for quantifying a specific compound has a reaction layer containing at least an enzyme, and an electrode system having a working electrode and a counter electrode formed on an insulating base plate; the biosensor detects the specific compound contained in a sample on the basis of an electrochemical response. In quantifying, the working electrode and the counter electrode are short-circuited before the voltage is applied therebetween. The short-circuiting eliminates measuring errors that may occur due to nonuniform dissolution of the reaction layer in a sample, and achieves highly reliable quantification of a specific compound.

Abstract: A biosensor of the present invention is provided with an insulating base plate, an electrode system mainly consisting of a working electrode and a counter electrode formed on the insulating base plate, and a reaction layer on the electrode system. The counter electrode is partially a circular arc. A manufacturing method of the biosensor of the present invention is comprised of a step to form a base by arranging leads, an electrode system, and an insulating layer on an insulating base plate, and a step to form a reaction layer mainly composed of an enzyme on the electrode system. Since the counter electrode is partially in the shape of a circular arc, the reaction layer is easily formed and prevented from delaminating, whereby the measuring accuracy, preservative properties and reliability of the biosensor are improved. The present invention enables highly efficient biosensors to be mass produced at low cost.

Abstract: A biosensor for rapid quantification of a specific component contained in various biological samples with high accuracy has an electrically insulating base, an electrode system including a working electrode and a counter electrode formed on one face of the insulating base, and a reaction layer formed on the insulating base in close contact with the electrode system. The reaction layer contains at least a hydrophilic polymer, a buffer and an enzyme which is separated from the buffer.