Abstract: A biological fluid analysis device including a biosensor is disclosed.

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

Abstract: A chemical sensor (1) for selectively detecting an analyte in a solution as described. The sensor comprises a flow-through chamber (2), a selective membrane (3), a transducer means (4), an inlet (5) for a liquid flow containing a recognition element, and an outlet (6). There is also described a method of selectively detecting an analyte in a solution, wherein a recognition element is contacted with the solution containing the analyte via a selective membrane, said contact resulting in a response detectable by transducer means. The recognition element is injected into a flow, the flow is passed into a flow-through chamber comprising a transducer means and the selective membrane, where it is contacted with the analyte passing from the solution outside the selective membrane, whereby the recognition element and the analyte interact to provide a signal which is detected by the transducer means.

Abstract: A method for determining the concentration of a reduced (or oxidised) form of a redox species in an electrochemical cell of the kind comprising a working electrode and a counter electrode spaced from the working electrode by a predetermined distance, said method comprising the steps of: (1) applying an electric potential difference between the electrodes; (2) selecting the potential of the working electrode such that the rate of electro-oxidation of the reduced form (or electro-reduction of the oxidised form) of the species is diffusion controlled, (3) selecting the spacing between the working electrode and the counter electrode so that reaction products from the counter electrode arrive at the working electrode; (4) determining current as a function of time after application of the potential and prior to achievement of a steady state; (5) estimating the magnitude of the steady state current, and (6) obtaining from the change in current with time and the magnitude of the steady state current, a value indicati

Abstract: Nitric oxide-specific electrodes are useful for in situ detection of nitric oxide in biomedical applications and have at least a surface region capable of forming complexes with nitric oxide. The nitric oxide complexes formed at the surface of the electrodes apparently increase the concentration of nitric oxide available for detection, leading to significantly improved relative responses as compared to other known nitric oxide electrode materials. The electrode has at least an exterior surface region which contains ruthenium and/or at least one oxide of ruthenium. The electrodes are pre-conditioned at a potential, or potentials, different than the working potential of the electrode, followed by further conditioning at the working potential. Direct response to nitric oxide has been observed for ruthenium electrodes at or below potentials about +675 mV vs. Ag/AgCl, while ruthenium electrodes paradoxical response to nitric oxide has been observed at potentials above +675 mV vs. Ag/Cl.

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

Abstract: The invention is concerned with a sensor for the determination of the concentration and the detection of an enzyme substrate in a liquid sample, the sensor comprising an enzyme capable of reacting with the enzyme substrate while producing a substance directly or indirectly detectable, a detection device for this substance and a cover membrane from a polymer permeable to the enzyme substrate, characterized in that the polymer is a polyvinyl chloride copolymer, i.e. a copolymer from vinyl chloride and a further monomer, the copolymer comprising hydrophilic groups. The sensor according to the invention may be provided as an optical sensor or as an amperometric sensor.

Abstract: A chemical sensor (1) for selectively detecting an analyte in a solution as described. The sensor comprises a flow-through chamber (2), a selective membrane (3), a transducer means (4), an inlet (5) for a liquid flow containing a recognition element, and an outlet (6). There is also described a method of selectively detecting an analyte in a solution, wherein a recognition element is contacted with the solution containing the analyte via a selective membrane, said contact resulting in a response detectable by transducer means. The recognition element is injected into a flow, the flow is passed into a flow-through chamber comprising a transducer means and the selective membrane, where it is contacted with the analyte passing from the solution outside the selective membrane, whereby the recognition element and the analyte interact to provide a signal which is detected by the transducer means.

Abstract: A method of determining the concentration of glycoproteins and glycosylated hemoglobin in whole blood and whole blood components by means of an amperometric biosensor and an amperometric biosensor for this determination are provided. In one embodiment, whole blood is introduced into a version of an amperometric sensor having a component that removes erythrocytes. Redox mediators are used to obtain a current flow based on the oxidation of fructosamine derivatives that can be correlated with the concentration of glycosylated proteins in the fraction of the blood from which erythrocytes have been excluded. To obtain the concentration of glycosylated hemoglobin, whole blood is introduced into a version of the sensor which includes a component that produces lysis of the erythrocytes yielding a current flow proportional to the total quality of glycosylated proteins including glycosylated hemoglobin.

Abstract: The invention provides an electrochemical reaction wherein a controlled amount of a first reagent is generated electrochemically at an electrode in electrical contact with a solution of an electrochemically inert salt, comprising applying a suitable electrical potential to the electrode for a suitable time to generate a controlled amount of the first reagent by electrochemical reaction between the electrode and a species in solution producing a localized thin layer environment comprising the first reagent in the vicinity of the electrode; and monitoring the amount or presence of the first reagent or a further species produced in solution in response to production of the first reagent. The method invention thus involves generating the first reagent in situ at an electrode.

Abstract: A sensor array for detecting a microorganism comprising first and second sensors electrically connected to an electrical measuring apparatus, wherein the sensors comprise a region of nonconducting organic material and a region of conducting material compositionally that is different than the nonconducting organic material and an electrical path through the regions of nonconducting organic material and the conducting material. A system for identifying microorganisms using the sensor array, a computer and a pattern recognition algorithm, such as a neural net are also disclosed.

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

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

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.

Abstract: Methods are described for extending the service life of implantable sensors having a silver-containing anodic reference electrode maintained at a high impedance, at least one noble metal cathodic working electrode, and at least one noble metal anodic counter electrode maintained at a low impedance, particularly sensors for the in vivo detection of oxygen and/or glucose in bodily fluids. The methods described involve increasing the input impedance of the reference electrode up to a maximum for implanted circuitry and shielding said electrode, and/or alternating the operating roles of the reference and working electrodes, switching the working electrodes with counter electrodes in the circuit, reversing the polarities of the reference and working electrodes, and sequentially activating each electrode in a plurality of working and/or reference electrodes in the circuit.

Abstract: A method for determining the concentration of a reduced or oxidized form of a redox species in an electrochemical cell (FIG. 10) of the kind comprising a working electrode (2) and a counter electrode (16) spaced from the working electrode such that reaction products from the counter electrode arrive at the working electrode, the method comprising the steps (FIG. 5) of applying (21) an electric potential between the electrodes, such that the electro-oxidation of the redox species is diffusion controlled, determining the current as a function of time, estimating the magnitude of the steady state current (23), reversing the potential, again determining current as a function of time and estimating the reverse potential steady state (25).

Abstract: A new electrochemical probe(s) design allowing for continuous (renewable) reagent delivery. The probe comprises an integrated membrane-sampling/electrochemical sensor that prevents interferences from surface-active materials and greatly extends the linear range. The probe(s) is useful for remote or laboratory-based monitoring in connection with microdialysis sampling and electrochemical measurements of metals and organic compounds that are not readily detected in the absence of reacting with the compound. Also disclosed is a method of using the probe(s).

Abstract: An amperometric sensor device comprising a working electrode, a reference/pseudo-reference electrode and a permselective membrane incorporating a charged organic species. The electrodes are in intimate contact with the membrane and are on a side of the membrane opposite to the side exposed to a fluid sample. The charged organic species provides a conducting path through the membrane between the electrodes.

Abstract: A method for indicating the concentration of a substance in solution includes passing an alternating voltage between a first electrode structure having coated thereon a polymer and a second separate counter electrode in the solution. The polymer is in one of an oxidized and a reduced state, between which states its conductivity varies. Changes in the conductivity of the polymer coating are measured, the measurement being representative of the state of the polymer and thereby of the concentration of the substance in the solution. Electrodes for use in this method are also described.

Abstract: Biosensor for amperometric measurements wherein the measuring electrode (34) is made of an electrically conductive carrier made of carbon which is saturated with a platinum metal in colloidal form wherein a lead-off contact (10) of vitreous carbon runs from the measuring electrode (34). The porous carrier (6) is saturated with an enzyme suitably glucose oxidase for the determination of glucose wherein the surface of the carrier (68) is protected against the environment by a membrane (70).

Abstract: The invention provides an electrochemical reaction wherein a controlled amount of a first reagent is generated electrochemically at an electrode in electrical contact with a solution of an electrochemically inert salt, comprising applying a suitable electrical potential to the electrode for a suitable time to generate a controlled amount of the first reagent by electrochemical reaction between the electrode and a species in solution producing a localized thin layer environment comprising the first reagent in the vicinity of the electrode; and monitoring the amount or presence of the first reagent or a further species produced in solution in response to production of the first reagent. The method invention thus involves generating the first reagent in situ at an electrode.

Abstract: The present invention provides for electrode assemblies and methods in which electron transfer between a redox reaction product and an electrically conductive electrode material is facilitated by a metallo macrocyclic compound, preferably a metallo isoindole ringed compound and more preferably a ferro isoindole ringed compound. The redox reaction is usually catalysized by a redox enzyme, such as an oxidase.

Abstract: An improved electrode assembly is disclosed for use in assaying glucose in solution, e.g., in undiluted whole blood. The assembly includes a sensor electrode and a special overlaying multi-layer membrane that can be sterilized by gamma radiation without reducing the activity of a glucose oxidase enzyme located in an intermediate layer of the membrane. An outer layer of the membrane is formed with microscopic pores having a predetermined density and predetermined size, for reliably controlling the flux of glucose and oxygen from the solution to the intermediate layer, where they react in the presence of the glucose oxidase enzyme to form reactions products that include hydrogen peroxide. The outer layer thus functions as a diffusion barrier, to eliminate the adverse effects of any oxygen deficit that might be present. In addition, an inner layer of the membrane functions as an interference barrier, for controlling the permeation of the hydrogen peroxide reaction product to the underlying electrode.

Abstract: The present invention provides for electrode assemblies and methods in which electron transfer between a redox reaction product and an electrically conductive electrode material is facilitated by a metallo macrocyclic compound, preferably a metallo isoindole ringed compound and more preferably a ferro isoindole ringed compound. The redox reaction is usually catalysized by a redox enzyme, such as an oxidase.

Abstract: Provided are microparticle forms of carbon, carbon catalysts and carbon-containing electrically conductive materials which are covalently linked to peroxidase. The carbon:peroxidase conjugates are suitable for use as substrates in conventional electrodes. Surprisingly, the conjugates display very little sensitivity to known interfering substances and thus are suitable for use as interference free electrodes.

Abstract: An electrochemical-enzymatic sensor for the determination of substances, in particular glucose, in body fluids, which possesses a good long-term stability, includes: a sensor electrode of electrocatalytically inactive carbon, a counterelectrode, a reference electrode, an enzyme-containing layer located before the sensor electrode, and a diaphragm of biocompatible, hydrophilic, oxygen-permeable material covering the enzyme layer toward the body fluid and retaining the enzyme.

Abstract: There is provided a sensor for the measurement of a content of a material in liquid which material is oxidized with an oxidase enzyme in which sensor a reagent layer is formed on an electrode system composed of a measuring electrode and a counter electrode both of which are formed on an insulating substrate, the reagent layer is composed of a hydrophilic polymer layer comprising a hydrophilic polymer and a reactive layer comprising the oxidase enzyme and an electron carrier, and the reagent layer further comprises a phosphate.

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 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 redox electrode for the rapid detection of glucose in aqueous media and a method for its use are provided. The redox electrode comprises an electrically conductive member such as copper, and a redox membrane in direct contact with said electrically conductive member. The redox membrane comprises a polymer matrix such as PVC containing a plasticizer, and a complex of 7,7,8,8-tetracyanoquinodimethane and tetrathiafulvalene with the complex having a burgundy-red coloration and characterized by a broad absorption from about 340 nm to about 550 nm and weaker absorption between about 650 nm to about 800 nm having about six small peaks with an absorption maximum at about 750 nm. Glucose is rapidly assayed by bringing the redox electrode and a reference electrode into simultaneous contact with an aqueous medium containing KCl, phosphate buffer, glucose oxidase, peroxidase, and 3,3',5,5'-tetramethylbenzidine dihydrochloride. The potential of the redox membrane is then monitored until it is stable.

Abstract: A regenerable biosensor probe adapted for positioning in a bioreactor comprises a selectively permeable interface membrane, a porous protein-receiving matrix adjacent to the interface membrane, an indicating electrode, an inlet conduit through which fresh protein conjugate may flow to the protein-receiving matrix, and an outlet conduit through which spent protein conjugate may be removed from the protein-receiving matrix. A selectively permeable interface membrane, which may be used in a biosensor system to separate biochemical, optical or other processes from an analyte matrix comprises a supporting mesh, a perfluorosulfonic acid polymer impregnated substrate and a homogenous film of perfluorosulfonic acid polymer.A method of preparing this interface membrane comprises fixing a substrate on to a supporting mesh to form a substrate membrane, casting a perfluorosulfonic and polymer on the substrate membrane and curing the product to so formed.

Abstract: Disclosed is an apparatus and method of equilibrating the dissolved gas composition of an aqueous fluid to reflect the predetermined gas composition contained in a gas equilibration reservoir. The equilibrated aqueous fluid can be used in a method of determining the concentration of a dissolved gas in a fluid sample. In one embodiment, the disclosed method is used to control the equilibrated gas composition of a calibrant fluid which, in turn, is used to measure the concentration of a dissolved gas, such as oxygen and carbon dioxide, in a sample fluid, such as whole blood.

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 miniaturized oxygen electrode having a small size exceeding the limit of miniaturization of the prior art electrode comprises an insulating substrate 21, 31 and, provided thereon, a pair of electrode patterns 22, 23 each comprising an active section 22A, 23A, a terminal section 22C, 23C for external connection, and a lead wire portion 22B, 23B for the connection thereof, the active sections 22A, 23A being mutually connected through an electrolyte-containing material 24, the electrolyte-containing material 24 being covered with an oxygen-permeable membrane 28, the lead wire portion 22B of at least one 22 of the electrode patterns extending below the active section 23A of at least one of other electrode patterns, 23, with an insulating layer 29 intervening between the lead wire portion 22B and the active section 23A.

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: Sensor devices for detecting components in fluid samples, especially by electrolytic analytical methods, comprising a detecting means (usually an anode, especially one of platinum) surrounded by a selectively permeable membrane barrier composed of a mixture of polyvinyl chloride and polyaryl sulphone polymers. Preferred proportions of the polymers are 1 to 9 parts of polyaryl sulphone for each part of polyvinyl chloride, and the mixture may be formed into membranes by solution casting. Preferably this barrier is used with an inner membrane, especially of porous polycarbonate. In use, these polymer mixtures are especially useful in their selective permeability to glucose. Also provided are methods for their use in analysis, and the polyvinyl chloride/polyaryl sulphone polymer compositions themselves and membranes made from them.

Abstract: Sensor devices comprising enzyme electrodes incorporating a microporous membrane coated with the carbonaceous material known as "diamond-like carbon" (most conveniently deposited by decomposition of a hydrocarbon, induced by radiation or a high electric field). The membrane material is preferably a polycarbonate and its thickness preferably less than 10 microns, and the coating is preferably 0.01 to 5 .mu.m thick. The preferred porosity is provided by pores of the order of 0.05 to 0.01 microns. The coated membrane imparts high resistance to fouling by contact with whole blood, extends the linearity of the electrode response over a substantially greater range, e.g. in the analytical determination of glucose in blood, and combines a high degree of restriction to passage of interferents while retaining high permeability to hydrogen peroxide and oxygen. Most conveniently used for amperometric measurements, especially using a Clark electrode pair, with an "active" anode of platinum.

Abstract: This invention relates to a process for performing enhanced selectivity potentiometric ion determinations using an asymmetric ion membrane electrode having an asymmetric membrane with a hydrophilic layer fused to an ion-selective layer.

Abstract: A redox electrode for the rapid detection of glucose in aqueous media and a method for its use are provided. The redox electrode comprises an electrically conductive member such as copper, and a redox membrane in direct contact with said electrically conductive member. The redox membrane comprises a polymer matrix such as PVC containing a plasticizer, and a complex of 7,7,8,8 -tetracyanoquinodimethane and tetrathiafulvalene with the complex having a burgundy-red coloration and characterized by a broad absorption from about 340 nm to about 550 nm and weaker absorption between about 650 nm to about 800 nm having about six small peaks with an absorption maximum at about 750nm. Glucose is rapidly assayed by bringing the redox electrode and a reference electrode into simultaneous contact with an aqueous medium containing KCl, phosphate buffer, glucose oxidase, peroxidase, and 3,3',5,5'-tetramethylbenzidine dihydrochloride. The potential of the redox membrane is then monitored until it is stable.

Abstract: Improved Newman type enzyme containing laminated membranes are disclosed for use in conjunction with polarographic cells to measure analyte concentration in solutions. The laminated membranes comprise a semipermeable outer, support layer including super large pores of greater than about 200 .ANG. in diameter. The outer layer preferably comprises pore sizes of about 380-750 .ANG. in diameter and has a percentage porosity of about 0.005-0.2%.

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.