Abstract: This invention provides a substrate concentration measuring method for measuring a concentration of a substrate included in a specimen based on an output for measurement from an enzyme electrode when the enzyme electrode and the substrate are reacted with each other, the substrate concentration is calculated using an output for correction from the enzyme electrode obtained when a reference solution whose substrate concentration is known and the enzyme electrode are reacted with each other before or after the enzyme electrode and the substrate are reacted with each other. For example, the output for correction is measured by each specimen. In this method, the substrate concentration may be calculated using the output for correction for the specimen to be measured and an output for correction corresponding to the at least one other specimen and measured prior to the output for correction.

Abstract: An electrochemical test sensor is adapted to measure glucose and correct for the oxygen effect in a fluid sample. The test sensor comprises a base, first and second working electrodes, and a counter electrode. The first working electrode includes glucose oxidase, a mediator and peroxidase. The second working electrode includes glucose oxidase and the mediator. The first working electrode, the second working electrode and the counter electrode are located on the base. In other embodiments, an electrochemical test sensor is adapted to measure cholesterol, lactate, pyruvate or xanthine and correct for the oxygen effect in a fluid sample.

Abstract: Described herein are systems and methods for distinguishing between a control solution and a blood sample. In one aspect, the methods include using a test strip in which multiple current transients are measured by a meter electrically connected to an electrochemical test strip. The current transients are used to determine if a sample is a blood sample or a control solution based on at least two characteristics. Further described herein are methods for calculating a discrimination criteria based upon at least two characteristics. Still further described herein are system for distinguishing between blood samples and control solutions.

Abstract: Methods and devices for determining the concentration of a constituent in a physiological sample are provided. The blood sample is introduced into a test strip with portions of the blood sample being directed to both a first capillary and a second capillary. The first capillary configured to electrochemically determine a concentration of a first analyte in a blood sample by measuring a signal across a set of electrodes. The second capillary is configured to determine a hematocrit value of the blood sample by measuring a signal across a second set of electrodes.

Abstract: A sensor system, device, and methods for determining the concentration of an analyte in a sample is described. Gated voltammetric pulse sequences including multiple duty cycles of sequential excitations and relaxations may provide a shorter analysis time and/or improve the accuracy and/or precision of the analysis. The disclosed pulse sequences may reduce analysis errors arising from the hematocrit effect, variance in cap-gap volumes, non-steady-state conditions, mediator background, a single set of calibration constants, under-fill, and changes in the active ionizing agent content of the sensor strip.

Abstract: Analytes in a liquid sample are determined by methods utilizing sample volumes of up to 1.0 ?l and test times from about 4 to about 9 seconds after detection of the sample. The methods are preferably performed using small test strips including a sample receiving chamber filled with the sample by capillary action.

Abstract: The present invention is directed to the detection of target analytes using electronic techniques, particularly AC techniques.

Abstract: A fluid sample is measured with a tear film measuring system that includes a processing device that receives a sample chip comprising a sample region configured to contain an aliquot volume of sample fluid, the processing device configured to perform analyses of osmolarity and of one or more biomarkers within the sample fluid, wherein the analysis of biomarkers includes normalization of biomarker concentration values.

Abstract: The presence of a select analyte such as glucose in the sample is evaluated in an electrochemical system using a conduction cell-type apparatus. A potential or current is generated between the two electrodes of the cell sufficient to bring about oxidation or reduction of the analyte or of a mediator in an analyte-detection redox system, thereby forming a chemical potential gradient of the analyte or mediator between the two electrodes after the gradient is established, the applied potential or current is discontinued and an analyte-independent signal is obtained from the relaxation of the chemical potential gradient. The analyte-independent signal is used to correct the analyte-dependent signal obtained during application of the potential or current.

Abstract: An electrochemical-based analytical test strip (“EBAT”) for the determination of an analyte in a bodily fluid sample includes an electrically insulating substrate layer with a distal end and a patterned conductor layer that is disposed over the electrically-insulating substrate layer and has a working electrode (“WE”) and a counter/reference electrode (“C/RE”). The EBAT also includes a patterned insulation layer with an electrode exposure window configured to expose a WE exposed portion and a C/RE exposed portion, an enzymatic reagent layer; and a patterned spacer layer. The patterned insulation layer and the patterned spacer layer define a sample receiving chamber with a sample-receiving opening (“SRO”) at the distal end of the electrically insulating substrate layer and that extends across the WE exposed portion and the C/RE exposed portion. Furthermore, the enzymatic reagent layer is disposed over the WE and C/RE exposed portions and extends no more than 400 ?m toward the SRO.

Abstract: Described and illustrated herein are systems and exemplary methods of operating an analyte measurement system having a meter and a test strip. In one embodiment, the method may be achieved by applying a first test voltage between a reference electrode and a second working electrode and applying a second test voltage between the reference electrode and a first working electrode; measuring a first test current, a second test current, a third test current and a fourth test current at the second working electrode after a blood sample containing an analyte is applied to the test strip; measuring a fifth test current at the first working electrode; estimating a hematocrit-corrected analyte concentration from the first, second, third, fourth and fifth test currents; and annunciating the hematocrit-corrected analyte concentration.

Abstract: Devices and methods are presented for electronic sensing of chemical and biochemical analytes. An electronic sensor having a at least two electrodes separated by a nanoscale gap wherein the separation between the first electrode and the second electrode forms a cavity capable of containing a fluid wherein two or more posts comprised of an insulating material extend into the cavity from the face of the first electrode to the face of the second electrode. Optionally, the cavity is closed with a bead. Devices according to embodiments of the invention are capable of detecting chemicals and biochemicals through redox cycling events. Additionally, devices and methods according to embodiments of the invention are adapted to identify and sequence nucleic acid molecules.

Abstract: A biosensor for measuring an analyte in a liquid sample includes a working electrode having a dispensed reagent thereon wherein the dispensed reagent contains an enzyme capable of catalyzing a reaction involving the analyte, a mediator that is considered an enzyme inhibitor, and an enzyme co-factor where the working electrode provides a stable and sensitive response even when the biosensor is stored at ambient conditions for a period of time selected from the group consisting of at least 3 months, 12 months and two years or more.

Abstract: In one form, a mutant fructosyl amino acid oxidase modified at an amino acid residue involved in a proton relay system is provided. The mutant fructosyl amino acid oxidase has reduced oxidase activity while substantially maintaining its dehydrogenase activity. Other forms include an assay device and assay method for measuring glycated protein. Still, other forms include unique methods, techniques, systems and devices involving a mutant fructosyl amino acid oxidase.

Abstract: A system and method for detecting a single-molecule using an integrated circuit which includes at least one membrane having a nanopore located between first and second reservoirs and a low-noise preamplifier having an electrode formed on the surface thereof is provided. The method includes passing a target molecule through the nanopore, and measuring a current through the nanopore to detect the presence of a biomolecular entity, if any.

Abstract: Among others, the present invention provides apparatus for detecting a disease, comprising a system delivery biological subject and a probing and detecting device, wherein the probing and detecting device includes a first micro-device and a first substrate supporting the first micro-device, the first micro-device contacts a biologic material to be detected and is capable of measuring at the microscopic level an electric, magnetic, electromagnetic, thermal, optical, acoustical, biological, chemical, physical, or mechanical property of the biologic material.

Abstract: Methods of determining a corrected analyte concentration in view of some error source are provided herein. The methods can be utilized for the determination of various analytes and/or various sources of error. In one example, the method can be configured to determine a corrected glucose concentration in view of an extreme level of hematocrit found within the sample. In other embodiments, methods are provided for identifying various system errors and/or defects. For example, such errors can include partial-fill or double-fill situations, high track resistance, and/or sample leakage. Systems are also provided for determining a corrected analyte concentration and/or detecting some system error.

Abstract: The present invention provides a method of electrochemically measuring a hematocrit (Hct) value using a sensor, capable of achieving excellent measurement accuracy and reliability and also provides a sensor used in the method. The method of electrochemically measuring a hematocrit (Hct) value of blood include: providing an electrode system having a working electrode (11) and a counter electrode (12), in which a redox substance is provided on the counter electrode (12) but not on the working electrode (11); supplying blood to the electrode system; applying a voltage to the electrode system in this state to cause an oxidation current or a reduction current to flow between the working electrode (11) and the counter electrode (12); detecting the oxidation current or the reduction current; and determining a Hct value based on a value of the detected current.

Abstract: A biosensor is disclosed comprising a support; a conductive layer composed of an electrical conductive material such as a noble metal, for example gold or palladium, and carbon; slits parallel to and perpendicular to the side of the support; working, counter, and detecting electrodes; a spacer which covers the working, counter, and detecting electrodes on the support; a rectangular cutout in the spacer forming a specimen supply path; an inlet to the specimen supply path; a reagent layer formed by applying a reagent containing an enzyme to the working, counter, and detecting electrodes, which are exposed through the cutout in the spacer; and a cover over the spacer. The biosensor can be formed by a simple method, and provides a uniform reagent layer on the electrodes regardless of the reagent composition.

Abstract: A method for distinguishing between types of electrochemical test sensors in a meter is disclosed. The method comprises the acts of providing an electrochemical test sensor comprising an enzyme and a chemical additive, contacting the test sensor to the meter to form an electrical connection, applying a potential having a magnitude sufficient to initiate a redox reaction of the chemical additive, and determining which type of electrochemical test sensor is being used based on whether a predetermined signal has been generated after the potential has been applied. The meter is adapted to determine an analyte concentration in a fluid sample.

Abstract: Disclosed is a modified glucose dehydrogenases that has dramatically increased productivity in Escherichia coli and dramatically increased thermal stability, which is obtained by introducing specific amino acid mutations to glucose dehydrogenase derived from Botryotinia fuckeliana. Also disclosed is a modified glucose dehydrogenases that has dramatically increased productivity in E. coli and dramatically increased thermal stability, which is obtained by replacing two amino acid residues in glucose dehydrogenase of fungal origin with cysteine residues. The novel glucose dehydrogenase has a low reactivity to xylose.

Abstract: Methods are disclosed for measuring substrate content in a specimen using a biosensor that includes two pairs of electrodes in a specimen supply path, where the methods include the steps of: (a) a first detecting step for detecting an electrical change in the first pair of electrodes; (b) a second detecting step for detecting an electrical change in the second pair of electrodes after the first detecting step; (c) a judging step for judging a shortage of specimen amount that is needed for measurement, when an electrical change is not detected in the second detecting step within a prescribed period of time after the first detecting step; (d) an indicating step for indicating a shortage of the specimen amount; and (e) a stopping step for stopping measurement of substrate content in the specimen once the shortage of specimen amount is indicated in the indicating step.

Abstract: The present invention provides: a reagent composition having higher storage stability; a sensor involving the reagent composition; and others. According to the present invention, a specific heterocyclic compound is added to a reagent composition to improve the storage stability of the reagent composition and reduce the degree of fluctuation in current values in a sensor that utilizes reagent composition.

Abstract: Quantifying devices and methods are disclosed for quantifying substrate content using a biosensor where the methods include a first detecting step for detecting an electrical change generated between a measuring electrode and a counter electrode of a biosensor by applying a sample liquid to the biosensor; a second detecting step for detecting an electrical change generated between a detecting electrode of the biosensor and the counter electrode or the measuring electrode by applying the sample liquid to the biosensor; and a notification step for informing a user when the second detecting step does not occur within a predetermined period after the first detecting step.

Abstract: Methods and systems for measuring the concentration of an analyte in a blood sample and, more particularly, to methods of chemistry patterning reagent layers for multiple well biosensors. A first capillary is first configured to receive a dispensed reagent layer such that the reagent layer is distributed in a substantially uniform manner within the first capillary. The first capillary may also configured to isolate the first capillary from other capillaries present in the biosensor. After the reagent layer has been dispensed and dried, the first capillary may then be reconfigured to allow the first capillary to receive a blood sample.

Abstract: Techniques and systems are disclosed for implementing textile-based screen-printed amperometric or potentiometric sensors. The chemical sensor can include carbon based electrodes to detect at least one of NADH, hydrogen peroxide, potassium ferrocyanide, TNT or DNT, in liquid or vapor phase. In one application, underwater presence of chemicals such as heavy metals and explosives is detected using the textile-based sensors.

Abstract: Described herein are systems and methods for distinguishing between a control solution and a blood sample. In one aspect, the methods include using a test strip in which multiple current transients are measured by a meter electrically connected to an electrochemical test strip. The current transients are used to determine if a sample is a blood sample or a control solution based on at least two characteristics. Further described herein are methods for calculating a discrimination criteria based upon at least two characteristics. Still further described herein are system for distinguishing between blood samples and control solutions.

Abstract: A sensor utilizing a non-leachable or diffusible redox mediator is described. The sensor includes a sample chamber to hold a sample in electrolytic contact with a working electrode, and in at least some instances, the sensor also contains a non-leachable or a diffusible second electron transfer agent. The sensor and/or the methods used produce a sensor signal in response to the analyte that can be distinguished from a background signal caused by the mediator. The invention can be used to determine the concentration of a biomolecule, such as glucose or lactate, in a biological fluid, such as blood or serum, using techniques such as coulometry, amperometry; and potentiometry. An enzyme capable of catalyzing the electrooxidation or electroreduction of the biomolecule is typically provided as a second electron transfer agent.

Abstract: This invention relates to a non-destructive means to determine electrochemical characteristics in biosensor test strips, including first applying a cyclic oxidative and reductive electric potential onto the inspection pads connecting to the reference electrode and working electrode, on which lies a drop of enzyme reagent solution, to homogenize the electrochemical characteristics of the biosensor test strips, and then applying an inspection electric potential within a short period of time over the inspection pads connecting to the reference electrode and working electrode to measure its electrical resistance to identify any abnormal biosensor test strips if present. Afterwards, embodiments of the present invention applies a reverse electric potential, having the same time interval as the inspection electric potential, onto the inspection pads connecting to the reference electrode and working electrode to prevent degradation on mediators such as potassium ferricyanide.

Abstract: Disclosed is a biosensor capable of measuring a total concentration of plural types of amino acids. An amino-acid biosensor (200) for measuring a total concentration of a plurality of specific amino acids, comprises a measuring electrode (202) which includes as components a mediator and an enzyme which selectively act on the plurality of specific amino acids each serving as a substrate, and a counter electrode (203). The enzyme has a substrate affinity to each of the plurality of specific amino acids. The enzyme is operable to catalyze a reaction in each of the plurality of specific amino acids as a substrate so as to form a reaction product, and the mediator is operable, during amino-acid concentration measurement, to carry electrons between the reaction product and the measuring electrode.

Abstract: The invention relates to novel compositions of 1,3-disubstituted ferrocenes useful for the modification of electrodes.

Abstract: A method and device are provided for measuring a level of a clinically relevant analyte (such as glucose) in a fluid (such as blood). The device includes a flow path for conducting said fluid through the device; a detection chamber arranged on said flow path; and detector means arranged to detect analyte levels in the fluid in said chamber, wherein: said detection chamber contains a predetermined amount of an analyte such that that analyte mixes with fluid in the detection chamber to form, at the detector means, a calibration sample of the fluid at a time after the arrival of the fluid in said detection chamber, and said detector means is arranged to detect a first analyte level of an unadulterated sample of the fluid at a first time which is before the formation of said calibration sample and to detect a second analyte level of said calibration sample at a second time which is after the formation of said calibration sample.

Abstract: Glucose and ATP biosensors have important applications in diagnostics and research. Combining single-walled carbon nanotubes (SWCNTs) with Pt nanoparticles can significantly enhance the performance of electrochemical biosensors. This disclosure illustrates the use of single-stranded DNA (ssDNA) to modify SWCNTs to increase SWCNT solubility in water. Multiple embodiments with this configuration allows for exploration of new schemes of combining ssDNASWCNT and Pt black in aqueous media systems. These embodiments resulted in a nanocomposite with enhanced biosensor performance. The ssDNA-SWCNT/Pt black nanocomposite constructed by a layered scheme proved most effective in terms of biosensor activity. The key feature of this structure and method of use is the exploitation of ssDNASWCNTs as molecular templates for Pt black electrodeposition. Glucose and ATP microbiosensors fabricated utilizing this structure and method of use exhibited high sensitivity, wide linear range and low limit of detection.

Abstract: The present invention is directed to electrochemical sensors and systems and methods for electrochemically sensing a particular constituent within a fluid through the use of a diagnostic test. The methods provide for automatic discrimination of sample from control or standard solutions. A device and system used to determine a constituent level within a fluid that employ such automatic sample discrimination methods or specially formulated solutions is also provided.

Abstract: The present invention relates to improved electrochemical biosensor strips and methods for determining the concentration of an analyte in a sample. By selectively measuring a measurable species residing in a diffusion barrier layer, to the substantial exclusion of the measurable species residing exterior to the diffusion barrier layer, measurement errors introduced by sample constituents, such as red blood cells, and manufacturing variances may be reduced.

Abstract: The disclosure also relates to novel compositions and methods for the single, direct detection of Hemoglobin A1c percentage in a sample, using conversion of functional groups attached to a transitional metal complex, resulting in quantifiable electrochemical signal at two unique potentials, Eo1 and Eo2.

Abstract: A disposable biosensor having improved long term storage stability including a working electrode and a reference electrode formed on an insulating substrate and a dissolvable reagent layer composition disposed directly on the working electrode where the reagent layer composition contains a glucose-based enzyme, a reagent component selected from a phosphate buffer and a tris reagent, and a redox mediator.

Abstract: A method for estimation of hematocrit of a sample having an analyte includes: bringing the sample into contact with a sensor strip including a reference electrode coated with a reference layer nonreactive to the analyte, and a working electrode coated with a working layer including a biorecognition element reactive to the analyte; applying a voltage between the reference and working electrodes, and recording information of a reaction current flowing through the sample within a time period of not greater than 5 seconds from beginning of application of the voltage; and estimating the hematocrit of the sample by analyzing the recorded information using a predetermined current-hematocrit function.

Abstract: A porous electrochemical electrode is made up of a solid cellular material provided in the form of a semi-graphitised carbon monolith comprising a hierarchised porous network free of mesopores and including macropores with a mean dimension dA of 1 ?m to 100 ?m, and micropores with a mean dimension dI of 0.5 nm to 2 nm, said macropores and micropores being interconnected. In said electrode, the macropores contain at least one electroactive species in direct contact with the semi-graphitised carbon that makes up the surface of the macropores. The invention also relates to a method for preparing such an electrode as well as to the use thereof as a biosensor or for manufacturing a biopile.

Abstract: A sensor utilizing a non-leachable or diffusible redox mediator is described. The sensor includes a sample chamber to hold a sample in electrolytic contact with a working electrode, and in at least some instances, the sensor also contains a non-leachable or a diffusible second electron transfer agent. The sensor and/or the methods used produce a sensor signal in response to the analyte that can be distinguished from a background signal caused by the mediator. The invention can be used to determine the concentration of a biomolecule, such as glucose or lactate, in a biological fluid, such as blood or serum, using techniques such as coulometry, amperometry, and potentiometry. An enzyme capable of catalyzing the electrooxidation or electroreduction of the biomolecule is typically provided as a second electron transfer agent.

Abstract: A method for determining impedance includes receiving a time varying voltage signal from a biosensor and receiving a time varying current signal from the biosensor. The time varying voltage signal and the time varying current signal are transformed to a domain that represents complex values. The impedance representative of the biosensor based upon the transformed time varying voltage signal and the time varying current signal is calculated.

Abstract: Analytes in a liquid sample are determined by methods utilizing sample volumes of up to 1.0 ?l and test times from about 4 to about 9 seconds after detection of the sample. The methods are preferably performed using small test strips including a sample receiving chamber filled with the sample by capillary action.

Abstract: A sensor system, device, and methods for determining the concentration of an analyte in a sample is described. Gated amperometric pulse sequences including multiple duty cycles of sequential excitations and relaxations may provide a shorter analysis time and/or improve the accuracy and/or precision of the analysis. The disclosed gated amperometric pulse sequences may reduce analysis errors arising from the hematocrit effect, variance in cap-gap volumes, non-steady-state conditions, mediator background, under-fill, temperature changes in the sample, and a single set of calibration constants.

Abstract: A high throughput biological screening assay comprising at least two anodes, at least two cathodes acting as the reference electrode, and a polymer membrane placed between each anode and cathode, wherein the at least two anodes comprise a biological culture, and wherein the at least two cathodes comprise an oxidizing agent and a buffering agent. The high throughput biological screening assay wherein the at least two cathodes are connected in parallel to simulate the connection between the same cathode and different anodes. The high throughput biological screening assay further including an external resistor or open circuit and means for measuring the voltage across the external resistor or open circuit. A method of measuring power generation using a single cathode as a reference electrode to monitor the biological production of energy. A method of correlating bacterial biofilm formation within an operational microbial fuel cell directly to current output.

Abstract: In vitro analyte sensors and methods of analyte determination are provided. Embodiments include sensors that include a pair of electrodes to monitor filling of the sample chamber with sample.

Abstract: The present invention provides methods and apparatuses for analyte detection.

Abstract: Devices and methods for determining the concentration of an analyte in a sample of liquid are provided.

Abstract: A biosensor comprises a space part for sucking and housing a sample formed of two upper and lower plates, the two plates being stuck together by an adhesive layer, the space part for sucking and housing the sample being constituted so as to be partially opened in the peripheral part and partially closed by the adhesive layer, and has a working electrode having at least glucose oxidase immobilized thereon and a counter electrode on the same plane of the plate.

Abstract: The present invention is based on the discovery of NAD+ and NADP+ mediator compounds that do not bind irreversibly to thiol groups in the active sites of intracellular dehydrogenase enzymes. Such mediator compounds avoid a common mode of enzyme inhibition. The mediators can therefore increase the stability and reliability of the electrical response in amperometric electrodes constructed from NAD- or NADP-dependent enzymes.

Abstract: A composition of redox-reagent containing metal-containing complex and thionine or its derivative as electron transfer mediator for use in an electrochemical biosensor, and a biosensor containing the same are provided. With the increase in reaction rate between redox enzyme-thionine (or its derivative)-metal-containing complex in the composition of redox-reagent containing metal-containing complex and thionine or its derivative, glucose detection efficiency markedly increases, and the composition is hardly influenced from high humidity and interfering substances. Accordingly, the composition of redox-reagent is useful in fabricating an electrochemical biosensor for detecting glucose in blood.