Abstract: This invention relates to a sensor for detecting an analyte in the presence of at least one interferent in a fluid sample. The sensor comprises a substrate, a channel disposed on the substrate, at least one transducer disposed in the channel, and a filter for selectively absorbing the analyte in preference to the at least one interferent. The filter is arranged in the channel remotely from the at least one transducer and the channel defines a flow path for the fluid sample such that the fluid sample contacts a first transducer to generate a first signal, followed by the filter, followed by the first transducer or a second transducer to generate a second signal.

Abstract: A thin film sensor, such as a glucose sensor, is provided for transcutaneous placement at a selected site within the body of a patient. The sensor includes several sensor layers that include conductive layers and includes a proximal segment defining conductive contacts adapted for electrical connection to a suitable monitor, and a distal segment with sensor electrodes for transcutaneous placement. The sensor electrode layers are disposed generally above each other, for example with the reference electrode above the working electrode and the working electrode above the counter electrode. The electrode layers are separated by dielectric layer.

Abstract: A biosensor comprises a substrate; a reference electrode; a working electrode; a counter electrode; and a plurality of permeability adjusting spacers. The reference electrode, the working electrode and the plurality of permeability adjusting spacers are all being disposed to be substantially parallel to each other to create a plurality of enzyme containing porous sections. The enzyme containing porous sections contain an enzyme; where the enzyme is operative to react with a metabolite to determine the concentration of the metabolite. By combining a number of the aforementioned biosensors, the differential concentration of a target enzyme or protein is determined by monitoring the changes on its metabolite substrates.

Abstract: An apparatus and methods for detecting at least one analyte of interest either produced or consumed by a plurality of cell. In one embodiment of the present invention, the method includes the steps of providing a housing defining a chamber, placing a plurality of cells in the chamber, and simultaneously detecting at least two analytes of interest either produced or consumed by the plurality of cells in the chamber.

Abstract: A polymer matrix that may coated on an electrode is created by co-crosslinking (1) an adduct of a polyaniline formed by templated oxidative polymerization on a polymer acid; (2) a water-soluble crosslinker; and (3) a redox enzyme. The polymer matrix may be hydrated, and the absorbed water may make it permeable to, for example, glucose. The polyaniline may be polyaniline itself or a substituted polyaniline; the water-soluble crosslinker may be poly(ethylene glycol) diglycidyl ether, and the redox enzyme may be glucose oxidase. The polymer matrix may be produced by co-crosslinking (1) an adduct of an electrically conductive polymer and a polymer acid; (2) a water-soluble crosslinker; and (3) a redox enzyme in a single step at an about neutral pH, curing by drying. After hydration, the crosslinked polymer matrix may form a 3-dimensional glucose-permeable bioelectrocatalyst, catalyzing the electrooxidation of glucose.

Abstract: A sensor for sensing and measuring a concentration of urea in a sample has an ammonium ion selective membrane and urease enzymes immobilized on the ammonium ion selective membrane. The urease enzymes enzymatically convert urea into ammonium ions, which is sensed by said ammonium ion selective membrane and transformed into a signal. A detector system is used for processing signal from said ammonium ion selective membrane to generate a response potential that corresponds to the concentration of urea in the sample.

Abstract: The invention relates to novel methods and compositions for the detection of analytes using the nuclear reorganization energy, ?, of an electron transfer process.

Abstract: The invention relates to novel methods and compositions for the detection of analytes using the nuclear reorganization energy, ?, of an electron transfer process.

Abstract: An apparatus and method for sensing time varying ionic current in an electrolytic system having a first fluid chamber and a second fluid chamber separated by a barrier structure is provided, wherein the barrier structure includes thick walls and a substrate having an orifice therein, with the first and second fluid chambers being in communication via the orifice. A potential is applied between electrodes in respective first and second fluid chambers, thus driving an electrical current between them and through the orifice. Total capacitance of the system is less than 10 pF. Analytes are added to one of the first and second fluid chambers and time varying ionic current that passes across the orifice is measured. An amplifier proximal to the barrier structure and electrodes amplifies the ionic current signal.

Abstract: The invention relates to novel methods and compositions for the detection of analytes using the nuclear reorganization energy, ?, of an electron transfer process.

Abstract: The present invention concerns methods for detecting micro-organisms in a sample, and apparatus comprising hollow fibre filter membranes for same.

Abstract: Electrochemical sensors for measuring an analyte in a subject are described. More particularly, devices for measurement of an analyte are disclosed incorporating a sensor comprising an enzyme layer in contact with an interference layer and a membrane comprising vinyl ester monomeric units covering at least a portion of the enzyme layer and at least a portion of the interference layer, the devices providing rapid and accurate analyte levels upon deployment.

Abstract: A BUN (blood urea nitrogen) sensor containing immobilized carbonic anhydrase and immobilized urease for the in vitro detection of urea nitrogen in blood and biological samples with improved performance and precision characteristics.

Abstract: A substantially planar electrochemical test strip for determination of the presence and/or quantity of an analyte in a sample is provided that has a first electrode, a first connector including two contact pads, and a first conductive lead extending between the first electrode and the first connector to establish a path for conduction of an electrical signal between the first electrode and the first connector; a second electrode, a second connector including one or more contact pads, and a second conductive lead extending between the second electrode and the second connector to establish a path for conduction of an electrical signal between the second electrode and the second connector, and a sample chamber for receiving a sample. The first and second electrode are disposed to contact a sample within the sample chamber such that an electrochemical signal is generated. The contact pad or pads of the second connector are between the contact pads of the first connector when viewed in the plane of the test strip.

Abstract: The invention relates to novel methods and compositions for the detection of analytes using the nuclear reorganization energy, ?, of an electron transfer process.

Abstract: An electrochemical test sensor for detecting the analyte concentration of a fluid test sample includes a base, a dielectric layer, a reagent layer and a lid. The base provides a flow path for the test sample having on its surface a counter electrode and a working electrode adapted to electrically communicate with a detector of electrical current. The dielectric layer forms a dielectric window therethrough. The reagent layer includes an enzyme that is adapted to react with the analyte. The lid is adapted to mate with the base and to assist in forming a capillary space with an opening for the introduction of the test sample thereto. At least a portion of the width of the counter electrode is greater than the width of the working electrode.

Abstract: Enzymatic biosensors and methods of producing distal tips for biosensor transducers for use in detecting one or more analytes selected from organic compounds susceptible to dehalogenation, organic compounds susceptible to oxygenation and organophosphate compounds susceptible to hydrolysis are disclosed herein, as well as biosensor arrays, methods of detecting and quantifying analytes within a mixture, and devices and methods for delivering reagents to enzymes disposed within the distal tip of a biosensor.

Abstract: An electrochemical sensor system and membrane and method thereof for increased accuracy and effective life of electrochemical and enzyme sensors.

Abstract: Described is an amperometric biosensor in thick film technology for the detection an/or determination of substances undergoing enzyme catalyzed reactions, especially glucose or lactate, comprising an inert carrier material, at least one transducer layer exhibiting a specific electrical conductivity ?>104 ?-1cm-1, and at least one bioactive layer with diffusion barrier function containing at least one enzyme specifically reacting with said substance to be measured, said bioactive layer exhibiting a specific electrical conductivity ?<1 ?-1cm-1 and said bioactive layer further effectively hinders other electroactive substances to reach the transducer layer within the time of measurement.

Abstract: Systems and methods of use for continuous analyte measurement of a host's vascular system are provided. In some embodiments, a continuous glucose measurement system includes a vascular access device, a sensor and sensor electronics, the system being configured for insertion into communication with a host's circulatory system.

Abstract: The current measuring device includes an upper solution chamber (3) and a lower solution chamber (8) whose bottom has a support layer (5) and measures a current flowing via an artificial lipid bilayer membrane (2) formed on a small hole (4) of the upper solution chamber (3), wherein the lower solution chamber (8) is provided below the upper solution chamber (3) by being surrounded with a bottom plate (6) and an interval keeping member (7a). An internal pressure of the lower solution chamber (8) is dropped so that the artificial lipid bilayer membrane (2) formed on the small hole (4) swells to the side of the lower solution chamber (8) so as to be thinner, and the thinner artificial lipid bilayer membrane (2) is supported by the support layer.

Abstract: A method of detecting and measuring levels of a sulfur-containing amino acid in a sample is provided. The method includes combining an enzyme with an aqueous solution possibly comprising a sulfur-containing amino acid. When a sulfur-containing amino acid is present in the solution, it reacts with the enzyme and produces hydrogen sulfide or ammonia. An electrochemical sensor is employed to detect the presence of hydrogen sulfide or ammonia in the solution, and thereby detect the presence of sulfur-containing amino acid. The concentration of sulfur-containing amino acid present in the sample can be quantitatively measured or calculated using this method.

Abstract: The present invention relates generally to systems and methods for increasing oxygen availability to implantable devices. The preferred embodiments provide a membrane system configured to provide protection of the device from the biological environment and/or a catalyst for enabling an enzymatic reaction, wherein the membrane system includes a polymer formed from a high oxygen soluble material. The high oxygen soluble polymer material is disposed adjacent to an oxygen-utilizing source on the implantable device so as to dynamically retain high oxygen availability to the oxygen-utilizing source during oxygen deficits. Membrane systems of the preferred embodiments are useful for implantable devices with oxygen-utilizing sources and/or that function in low oxygen environments, such as enzyme-based electrochemical sensors and cell transplantation devices.

Abstract: The invention relates to novel methods and compositions for the detection of analytes using the nuclear reorganization energy, ?, of an electron transfer process.

Abstract: Provided herein is a stabilized oxygen transport matrix that includes a reversible oxygen binding protein, such as hemoglobin, immobilized throughout the stabilized oxygen transport matrix. The stabilized oxygen transport matrix is used to transport oxygen and can be used as an oxygen transport region and a reaction region of an analyte sensor, such as an implantable glucose sensor. The reversible binding protein can also function as an oxygen probe within the analyte sensor.

Abstract: An electrochemical test sensor adapted to assist in determining the concentration of analyte in a fluid sample is disclosed. The sensor comprises a base that assists in forming an opening for introducing the fluid sample, a working electrode being coupled to the base, and a counter electrode being coupled to the base, the counter electrode and the working electrode being adapted to be in electrical communication with a detector of electrical current, and a sub-element being coupled to the base. A major portion of the counter electrode is located downstream relative to the opening and at least a portion of the working electrode. The sub-element is located upstream relative to the working electrode such that when electrical communication occurs between only the sub-element and the working electrode there is insufficient flow of electrical current through the detector to determine the concentration of the analyte in the fluid sample.

Abstract: The present invention relates generally to systems and methods for increasing oxygen generation in electrochemical sensors in order to overcome the oxygen limitations. The preferred embodiments employ electrode systems with at least two electrodes in relatively close proximity to each other; wherein at least one electrode is configured to generate oxygen and at least one other electrode is configured to sense an analyte or a product of a reaction indicative of the concentration of analyte. The oxygen generated by the oxygen-generating electrode is available to the catalyst within a membrane system and/or the counter electrode, thereby enabling the electrochemical sensors of the preferred embodiments to function even during ischemic conditions.

Abstract: A novel biosensor was accomplished using a plasma-polymerized membrane. The biosensor of the present invention is a high-performance biosensor produced by a simpler method and applicable to a wide range of fields.

Abstract: Sensors (10, 110, 210, 310, 410) and a method for detecting an analyte are described. Sensors (10, 110, 210, 310, 410) each have a volume of a hydrophilic medium (24) that retains an amount of analyte proportionate to the concentration of analyte in a biological fluid, electrodes (12) and a redox enzyme in contact with medium (24), and an electron transfer mediator. The fluid contacts sensors (10, 110, 210, 310, 410) and at initially predetermined intervals intermittently applies a potential to electrode (12) sufficient to oxidize the mediator and sensing current through electrode (12) as a function of the duration of the applied potential. The applied mediator oxidizing applied potential is maintained for a period of time sufficient to determine the rate of change of current with time through electrode (12). The current flow is correlated with the current flow for known concentrations of the analyte in medium (24).

Abstract: The invention relates to novel methods and compositions for the detection of analytes using the nuclear reorganization energy, ?, of an electron transfer process.

Abstract: This invention relates to a biosensor and more particularly to an electrochemical biosensor for determining the concentration of an analyte in a carrier. The invention is particularly useful for determining the concentration of glucose in blood and is described herein with reference to that use but it should be understood that the invention is applicable to other analytic determinations.

Abstract: An electrochemical sensor system and membrane and method thereof for increased accuracy and effective life of electrochemical and enzyme sensors.

Abstract: A micron-scale self-referencing microsensor is disclosed which uses an enzyme-based electrode to measure the flux of an electrochemically inactive analyte such as glucose. The electrode oscillates between at least two positions. In the presence of the analyte, the enzyme generates a species detectable by the electrode.

Abstract: A method of determining the concentration of an analyte in a fluid test sample that includes providing an electrochemical sensor adapted to measure the analyte in the test sample. The test sample sufficiently covers a counter and working electrode of the electrochemical sensor. A first potential is applied between the counter and working electrodes for a first predetermined time period and the current is measured and the time is recorded. After the first potential is removed or substantially reduced, a second potential is applied between the counter and working electrodes and the current is measured. The concentration of the analyte is determined in the test sample as a function of the current measured. An index is calculated and compared to at least one predetermined parameter to identify when a bias, if any, exceeds a threshold. An error signal or analyte concentration is displayed depending on the comparison.

Abstract: The invention is the design of a biological measuring device for the determination of the concentration of biomolecules (e.g. glucose) in an environment which is designed for implantation into an individual or for use in the context of an external apparatus. The device contains a composite membrane that is essentially entirely permeable to oxygen and permeable to larger biomolecules only in discrete hydrophilic regions. The membrane diffusionally limits the access of biomolecules to an enzyme, present in the hydrophilic region that catalyzes the oxidation of the biomolecule to produce hydrogen peroxide. A sensor in communication with the hydrophilic region is used to determine the amount of product produced or the amount of excess oxygen present allowing for the concentration of the biomolecule to be determined.

Abstract: A chemical sensor selectively detects an analyte in a solution. The sensor comprises a flow-through chamber, a selective membrane, a transducer, an inlet for a liquid flow containing a recognition element, and an outlet. To detect an analyte in a solution, a recognition element is contacted with the solution containing the analyte via a selective membrane. This results in a response detectable by a transducer. The recognition element is injected into a flow, and the flow is passed into a flow-through chamber comprising the transducer and the selective membrane, where it contacts the analyte passing from the solution outside the chamber. The recognition element and the analyte interact to provide a signal that is detected by the transducer. The chemical sensor is used for detecting analyte(s) in a reactor system, a flow system or in an in vivo system.

Abstract: An electrochemical biosensor for quantifying one or more redox species in a liquid sample comprising a background electrochemical activity, wherein said biosensor comprises:

Abstract: The invention relates to electrodes which are provided with molecules that can bind macromolecular biopolymerss. A first electric measurement is carried out on the electrodes. A medium is contacted to said electrodes in such a way that biopolymers can specifically bind to first molecules or second molecules which are applied to the electrodes, when macromolecular biopolymers are present in the medium. Unbound first or second molecules are removed from the respective electrode and a second electric measurement is carried out. The macromolecular biopolymers are detected according to the measurements.

Abstract: A method for evaluating a polymer molecule including linearly connected monomer residues includes providing a polymer molecule in a liquid, contacting the liquid with an insulating solid-state membrane having a detector capable of detecting polymer molecule characteristics, and causing the polymer molecule to traverse a limited region of the solid-state membrane so that monomers of the polymer molecule traverse the limit region in sequential order, whereby the polymer molecule interacts linearly with the detector and data suitable to determine polymer molecule characteristics are obtained. The limited region may be defined by a nanometer-sized aperture in the membrane.

Abstract: A sensor probe is disclosed which can measure the hydrogen peroxide content of a single sample using two oxygen sensors whose electrodes are encased in defined membranes. The oxygen reference sensor is encased in a hydrophobic membrane which prevents the transport of hydrogen peroxide or electrochemical poisons or interferents and isolates the electrodes and an electrolyte fluid surrounding the electrodes from the sample fluid. The hydrogen-peroxide-generated oxygen (HPGO) sensor is also is encased in such a hydrophobic membrane, but has in series with and distally of the hydrophobic membrane a hydrophilic membrane which contains an immobilized enzyme such as catalase, peroxidase or other enzymes of a family which catalyzes the reaction of hydrogen peroxide to oxygen and water. At the HPGO sensor, the hydrogen peroxide is catalyzed to oxygen by the enzyme so that the HPGO sensor measures an enhanced concentration of oxygen relative to the oxygen reference sensor.

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 relates to a membrane for use in detecting the presence of an analyte. The membrane comprises an array of closely packed self-assembling amphiphilic molecules and a plurality of first and second receptor molecules, the first receptor molecules being reactive with one site on the analyte and second receptor molecules being reactive with another site on the analyte. The first receptor molecules are prevented from lateral diffusion within the membrane whilst the second receptor molecules are free to diffuse laterally within the membrane. The membrane is characterized in that the ratio of first receptor molecules to second receptor molecules is 10:1 or greater.

Abstract: Systems for positioning and/or analyzing samples such as cells, vesicles, cellular organelles, and fragments, derivatives, and mixtures thereof, for electrical and/or optical analysis, especially relating to the presence and/or activity of ion channels.

Abstract: A bilateral biosensor based upon a microporous architecture is provided which seeks to reduce the effect of co-reactant concentration limitations by utilizing a new sensor microgeometry. If implemented on the appropriate scale, the new sensor design augments substantially the concentration of oxygen, or other co-reactants or reagents, in the reaction zone of the sensor. Performance enhancements over traditional microscale devices employing unilateral orientation are accomplished, in one embodiment, by allowing analyte to enter the sensor from one side of the sensor, while allowing a co-substrate to enter from both sides of the sensor.

Abstract: A system and method for rapid hydration and reduced out-of-warm-up baseline drift for chemical, electrochemical and enzyme sensors.

Abstract: The present invention provides biosensors which include or are fabricated using optically sensitive moieties. The use of optically sensitive moieties provides advantages in the synthesis of the biosensors. Further the inclusion of optically sensitive moieties in the biosensor membrane provides an increase in the sensitivity of detection.

Abstract: An Electrochemical biosensor system which can do selectively quantitative analysis of blood sugar, cholesterol and other elements in blood is disclosed. The electrochemical biosensor test strip used in this invention is provided with recognition electrode which indicates that a fixed reagent is used for what material's quantitative analysis. The readout meter used in this invention discriminates the use of inserted test strip by auto-recognition of the location of said recognition electrode and performs predetermined algorithm. According to this invention, it has advantage that various blood elements such as blood sugar, cholesterol, GOT and GPT can be analyzed quantitatively by one readout meter.

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: 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.