Abstract: A biosensor enabling accurate measurement of the concentration of a substrate contained in a trace amount of a sample solution is disclosed. The electrochemical analysis element in accordance with the present invention which should be included in the biosensor comprises a sensor body having a hollow space which space is open at its both ends, an electrode system having a working electrode and a counter electrode, a reagent segment containing an enzyme, wherein the electrode system and the reagent segment are disposed on an inner wall of the hollow space.

Abstract: A biosensor that enables rapid and simple quantitation of a substrate with high accuracy and demonstrates an excellent preservation characteristic by best retaining enzyme activity is disclosed. The biosensor comprises an electrically insulating base plate, an electrode system including at least a working electrode and a counter electrode formed on the base plate, and a reaction layer containing at least an enzyme and a sugar. The reaction layer may be formed on the electrode system. The enzyme may be selected from glucose oxidase, glucose dehydrogenase, and fructose dehydrogenase. The sugar is trehalose, sucrose, glycerol, mannitol, and ribose. If the enzyme selected is glucose dehydrogenase whose coenzyme is pyrrolo-quinoline quinone, the use of trehalose is preferable.

Abstract: The present invention provides a biosensor having a favorable response characteristic up to a high concentration range, a low blank response and a high storage stability. This sensor comprises an electrode system including a working electrode and a counter electrode, for forming an electrochemical measurement system by coming in contact with a supplied solution; an electrically insulating supporting member for supporting the electrode system; a first reagent layer formed on the working electrode; and a second reagent layer formed on the counter electrode, wherein the first reagent layer comprises an enzyme as the main component, and the second reagent layer comprises an electron mediator as the main component.

Abstract: There is provided a cholesterol sensor with high-accuracy and excellent response, whose object to be measured is whole blood, where plasma with hemocytes therein filtered can rapidly reach an electrode system. In a biosensor where plasma with hemocytes therein filtered with a filter is sucked into a sample solution supply pathway due to capillarity, there are formed: a first pressing part for holding a primary side portion of the filter from the bottom; a second pressing part for holding a secondary side portion of the filter from the top and the bottom; a third pressing part for holding the central portion of the filter from the top; and a void for surrounding the filter between the second pressing part and third pressing part.

Abstract: A biosensor that is highly responsive and capable of rapid and highly sensitive quantification of a specific component contained in a sample is provided. The biosensor of this invention comprises: an electrically insulating base plate; an electrode system comprising a working electrode and a counter electrode disposed on the base plate; and a reagent system comprising an oxidoreductase which catalyzes the oxidation reaction of glucose, gluconolactonase and a buffer. The buffer is selected from the group consisting of phthalic acid and its salts, maleic acid and its salts, succinic acid and its salts, phospholic acid and its salts, acetic acid and its salts, boric acid and its salts, citric acid and its salts, glycine, tris(hydroxymethyl)aminomethane, piperazine-N,N′-bis(2-ethane sulfonic acid) and the like.

Abstract: The present invention provides a biosensor having a favorable response characteristic up to a high concentration range, a low blank response and a high storage stability. This sensor comprises an electrode system including a working electrode and a counter electrode, for forming an electrochemical measurement system by coming in contact with a supplied solution; an electrically insulating supporting member for supporting the electrode system; a first reagent layer formed on the working electrode; and a second reagent layer formed on the counter electrode, wherein the first reagent layer comprises an enzyme as the main component, and the second reagent layer comprises an electron mediator as the main component.

Abstract: The present invention provides a so improved biosensor that a whole blood is allowed to be an object to be measured, and that plasma of a blood, with hemocytes thereof having been filtered out, is allowed to quickly reach an electrode system.

Abstract: In order to provide a cholesterol sensor capable of measuring whole blood with high accuracy and excellent response, where plasma with hemocytes therein filtered promptly reaches an electrode system, in a biosensor comprising: an insulating base plate; an electrode system which is provided on the base plate and has a measurement electrode and a counter electrode; a reaction layer including at least oxidoreductase and an electron mediator; a sample solution supply pathway which includes the electrode system and the reaction layer and has an air aperture on the termination side thereof; a sample supply portion; and a filter which is disposed between the sample solution supply pathway and the sample supply portion and filters hemocytes, where plasma with the hemocytes therein filtered with the filter is sucked into the sample solution supply pathway due to capillarity, the central part of a secondary side portion of the filter is protruded into the sample solution supply pathway more than both the right and left

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: The present invention provides a highly sensitive biosensor that needs a smaller amount of sample for measurement. The biosensor comprises a first insulating base plate having a working electrode, a second insulating base plate having a counter electrode opposed to the working electrode, a reagent layer comprising at least an oxidoreductase, and a sample supply pathway formed between the first and second insulating base plates, wherein the working electrode, counter electrode and reagent layer are exposed to an inside of the sample supply pathway, and the distance between the working electrode and the counter electrode is 150 &mgr;m or less.

Abstract: A biosensor enabling accurate measurement of the concentration of a substrate contained in a trace amount of a sample solution is disclosed. The electrochemical analysis element in accordance with the present invention which should be included in the biosensor comprises a sensor body having a hollow space which space is open at its both ends, an electrode system having a working electrode and a counter electrode, a reagent segment containing an enzyme, wherein the electrode system and the reagent segment are disposed on an inner wall of the hollow space.

Abstract: The present invention provides an analytical element which is free from evaporation of a sample during measurement and therefore capable of quantifying a substrate using a very small amount of sample with high accuracy and which is free from scattering of the sample during and after the measurement and therefore hygienically excellent; and a measuring device and a substrate quantification method using the same. The analytical element comprises a cavity for accommodating a sample, a working electrode and a counter electrode exposed to an inside of the cavity, a reagent layer which comprises at least an oxidoreductase and is formed inside or in the vicinity of the cavity, an opening communicating with the cavity and a member covering the opening.

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: The present invention provides a biosensor that enables highly-accurate measurement of a sample solution including a solid component like hemocytes and has a little variation in response. The biosensor includes: an insulating base plate, an electrode system having at least a working electrode and a counter electrode provided on the base plate, a cover member that is combined with the base plate to define a sample solution supply pathway for leading a sample solution from a sample supply unit to the electrode system, a reaction reagent system including at least an oxidation-reduction enzyme and an electron mediator, and a filter disposed between the electrode system and the sample supply unit in the sample solution supply pathway. The biosensor has a space that encircles surface of the filter in an area from one end of the filter close to the sample supply unit to the other end of the filter close to the electrode system.

Abstract: The present invention provides a biosensor having a high current response sensitivity, a low blank response and a high storage stability. This sensor comprises an electrode system including a working electrode and a counter electrode, for forming an electrochemical measurement system by coming in contact with a supplied solution; an insulating supporting member for supporting the electrode system; a first reagent layer formed on the working electrode; and a second reagent layer formed on the counter electrode, wherein the first reagent layer does not contain an enzyme, but it contains at least an electron mediator, and the second reagent layer does not contain an electron mediator, but it contains at least an enzyme.

Abstract: Disclosed is a highly responsive biosensor comprising a cholesterol-oxidizing enzyme and cholesterol esterase. The biosensor comprises: an electrically insulating base plate; an electrode system including a working electrode and a counter electrode formed on the base plate; a cover member joined with the base plate to define a sample supply pathway through which a sample solution is introduced from a sample supply port to the electrode system, the sample supply pathway being formed between the cover member and the base plate; and a reagent layer formed in the sample supply pathway, wherein the reagent layer contains a cholesterol-oxidizing enzyme, cholesterol esterase, an electron mediator, and a buffer having a buffering capacity in an acidic pH range.

Abstract: The present invention provides a biosensor that has a reaction reagent system easily dissolved even in a sample solution containing a high concentration of a substrate and ensures rapid and highly accurate measurement. The method of forming a target reaction layer according to the present invention dissolves a material constituting the target reaction layer in a solvent of a sublimable substance to prepare a solution, applies the solution in a desired area to form the target reaction layer, freezes the applied solution, and sublimates the solvent included in a solid matter of the frozen solution under reduced pressure for removal. The resultant reaction layer has a large surface area and is easily dissolved in the sample solution to enable rapid measurement.

Abstract: The present invention provides a biosensor which enables prompt quantification by facilitating introduction of a sample solution even when the amount of the sample solution is small and improving dissolution of reagents. The biosensor comprises an insulating base plate; an electrode system including at least a measuring electrode and a counter electrode formed on the base plate; a cover member integrated into the base plate to form a sample solution supply pathway for supplying a sample solution to the electrode system between the cover member and the base plate; a reaction reagent system including at least an electron mediator and an oxidoreductase; and a carrier supporting at least the electron mediator or the oxidoreductase of the reaction reagent system, wherein the carrier is partially or wholly disposed outside the sample solution supply pathway.

Abstract: The present invention relates to a biosensor comprising a working electrode base plate 11, a counter electrode base plate 14 and a reagent layer containing at least an enzyme and an electron mediator, wherein a working electrode 12 disposed on the working electrode base plate and a counter electrode 15 disposed on the counter electrode base plate are positioned so as to mutually face and a terminal of a measuring device can be brought in contact with terminals 13, 16 of both electrodes from through-holes 25, 24. Such a biosensor can produce highly reliable and accurate measuring results with only a small amount of a sample.

Abstract: The present disclosure relates to a method for determining cholesterol in low density lipoprotein comprising the steps of (a) measuring total cholesterol level in a sample containing at least high density lipoprotein, low density lipoprotein, very low density lipoprotein and chylomicron, and (b) measuring cholesterol levels in the high density lipoprotein, very low density lipoprotein and chylomicron in the sample, wherein the cholesterol level in the low density lipoprotein is determined by subtracting a value obtained in step (b) from a value obtained in step (a). The present invention enables concurrent determination of cholesterol level in low density lipoprotein and total cholesterol level, facilitating acquisition of two types of biological information at a time.