Abstract: The present invention provides a novel biosensor for the detection of chemicals of interest. The novel biosensor of the present invention comprises an electrode having a catalytically active cyclodextrin attached thereto. The present invention will be useful for the detection of materials in a wide variety of samples. In particular, the present invention will permit the detection of nitrophenyl esters.

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: The invention relates to reference electrodes for use in voltammetric measuring chains for oxidative as well as reductive detection of analytes, which are open with respect to the measuring medium. A metal-containing phthalocyanine or a metalloporphyrin is employed as potential-determining electrode material for reference electrodes of the invention used in oxidative detection. A fourth period metal, preferably copper, and a salt of said metal is employed as potential-determining electrode material for reference electrodes of the invention used in reductive detection. The potential-determining electrode material is coated as a layer or component of a layer on a planar support. The open reference electrodes according to the invention are particularly suited for voltammetric chemo- or biosensors having a planar structure.

Abstract: An object of the present invention is to provide an electrode and a field effect transistor having excellent ion selectivity using a noncyclic peptide. In order to achieve the above object, the ion sensor of the present invention using a noncyclic peptide is an ion sensor where a noncyclic peptide is contained in a sensing membrane. The said noncyclic peptide may contain at least two kinds of natural amino acids or non-natural amino acids. The ion sensor of the present invention may be constituted by an ion-selective electrode or by an ion-selective field effect transistor. Examples of the main responding ion are magnesium ion, lead ion, potassium ion, calcium ion, nickel ion, copper ion, zinc ion and cadmium ion.

Abstract: A molecular recognition sensor system for detecting the presence and concentration of an analyte including a resistive sensor having a semiconductive polymer film which swells when exposed to an analyte and interferents and a molecular imprinted resistive sensor having a semiconductive polymer film imprinted with the analyte which thereby swells when exposed to interferents, a circuit connected to the resistive sensor and the molecular imprinted resistive sensor for detecting a change in the resistance of the resistive sensor when exposed to the analyte and the interferents, the change in the resistance of the molecular imprinted resistive sensor when exposed to the analyte and interferents, and for subtracting the change in resistance of the molecular imprinted resistive sensor from the change in resistance of the resistive sensor to reduce the effect of any interferents on the change in resistance of the resistive sensor thereby determining the presence and concentration of the analyte.

Abstract: Disclosed is a method for fabricating biosensors, using hydrophilic polyurethane. Bio-active reagents, including enzymes, antibodies, antigens, cells and receptors, are mixed with hydrophilic polyurethane and the mixture is directly coated over a signal transducer to form a sensing film which serves as a signal detector. The method using hydrophilic polyurethane allows the simplification of the fabrication of biosensors without conducting complicated chemical reactions and washing steps, such as crosslinking. The bio-active reagent entrapped within the hydrophilic polyurethane film can retains its high activity for an extended period of time and the intrinsic potentiometric response of the underlying ion-selective polymeric membrane is not affected by the bio-active reagent immobilized polyurethane film coated on its sensing surface. Therefore, the biosensors are superior in specificity, selectivity, and stability.

Abstract: A lithium ion-selective membrane that favors the bonding of lithium and depresses sodium interference is invented by a charge balance approach. A lithium ion-selective electrode (Li-ISE) having the membrane of this invention demonstrates a fast kinetic response, good precision and reproducibility, high sensitivity and the ability to retain the sensitivity after a long-term contact with biological samples. The sensor shows Nernst linearity with a slope of 55.4 mV for lithium ion concentrations between 0.5 &mgr;mol/L and 10 mmol/L. The membrane includes at least about 2% by weight of 6,6-dibenzyl-1,4,8,11 tetraoxacyclotetradecane ionophore; from about 0.025% to about 1% by weight of potassium tetrakis(4-chlorophenyl)borate additive; a plasticizer; and a polymeric material.

Abstract: A biosensor apparatus for detecting a binding event between a ligand and receptor. The apparatus includes a biosensor surface and surface-bound two-subunit heterodimer complexes composed of first and second, preferably oppositely charged peptides that together form an &agr;-helical coiled-coil heterodimer. The first peptide is attached to the biosensor surface, and the second peptide carries the ligand, accessible for binding by a ligand-binding agent. Binding of anti-ligand binding agent to the surface-bound ligand is detected by a suitable detector. A ligand-specific biosensor surface can be readily prepared from a universal template containing the first charged peptide, by addition of a selected ligand attached to the second peptide.

Abstract: The invention is directed to an anion-complexing compound with the formula I wherein R1 is a six-membered ring, Y′ is —NHC(X)NH—, and Y″ is selected from the group consisting of —NHC(X′)—, —C(X′)NH—, and —NHC(X′) NH—; and wherein X and X′, independently of one another, is a sulphur or oxygen atom. R4 and R4′ are either identical represented by a variety of groups or together represent a group such that the compound has a macrocyclic structure. The invention is also directed to a method of preparing such a compound, an ion-selective membrane, as well as a sensor provided with such a compound or membrane.

Abstract: On an insulating substrate 1 is formed an electrode 2, on which is then formed a protection layer 3 consisting of a methacrylate-resin polyfluoroalcohol ester layer.

Abstract: A biosensor apparatus for detecting a binding event between a ligand and receptor. The apparatus includes a biosensor surface and surface-bound two-subunit heterodimer complexes composed of first and second, preferably oppositely charged peptides that together form an &agr;-helical coiled-coil heterodimer. The-first peptide is attached to the biosensor surface, and the second peptide carries the ligand, accessible for binding by a ligand-binding agent. Binding of anti-ligand binding agent to the surface-bound ligand is detected by a suitable detector. A ligand-specific biosensor surface can be readily prepared from a universal template containing the first charged peptide, by addition of a selected ligand attached to the second peptide.

Abstract: An amperometric electrochemical gas sensor includes a permanent electrical resistance means disposed between two electrodes, one of which is the working electrode, the electrical resistance means having an electrical resistance of between about 10&OHgr; and 200 k&OHgr;. This resistance means provides a permanent shorting link between the electrodes, and constantly maintains the sensor in a ready-to-work condition.

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: An amperometric electrochemical gas sensor includes a permanent electrical resistance means disposed between two electrodes, one of which is the working electrode, the electrical resistance means having an electrical resistance of between about 10 &OHgr; and 200 k&OHgr;. This resistance means provides a permanent shorting link between the electrodes, and constantly maintains the sensor in a ready-to-work condition.

Abstract: The present invention provides a membrane based biosensor. The biosensor includes an electrode and a passivating layer bound to the electrode. A lipid membrane incorporating ionophores, the conductivity of the membrane being dependent on the presence or absence of an analyte, is bound to the passivating layer in a manner such that an ionic reservoir exists between the membrane and the passivating layer. Reservoir spanning molecules spanning the ionic reservoir are also included. These molecules are covalently attached at one end to the membrane and at the other to the passivating layer. The incorporation of the passivating provides greater stability to the sensor.

Abstract: The present invention relates to the compound of formula (I) useful as an intercalator in electrochemical detection of double-stranded DNAs, and a method for preparation thereof: 1

Abstract: The present invention is an apparatus for laboratory and field use in detecting and measuring Hg+ and Hg2+ in sample. A selective mercury binding agent, such as a chelating agent or clathrating agent, is covalently bound in a copolymer and deposited as an electrode layer. To prepare the preferred apparatus of the invention, thiophene, or other, similar monomer, is derivatized by covalent attachment thereto of Kryptofix-21™ (1,4,10-trioxa-7,13-diazacyclopentadecane) in the 3-position. The thiophene monomer and Kryptofix-21™ are co-polymerized and electrodeposited by known techniques onto a conductive substrate, such as platinum or glassy carbon, to obtain a multi-layer polymer coating of desired thickness. The resulting coated electrode has selective coordination sites for mercury of the order of Kf=1016, compared to Kf=103 for cadmium, Kf=105 for lead and Kf=105 for silver.

Abstract: Improved dry-operative ion-selective electrodes and their use are described. The dry-operative ion-selective electrodes include an internal reference electrode comprising a water-soluble salt dispersed in a polymer binder consisting essentially of a monomer having at least one carboxyl group and a hydrophobic monomer. The polymer provides reduced brittleness, good interlayer adhesion and high salt tolerance.

Abstract: Methods combining the creation of small bilayer membranes with the fusion of native cell membrane vesicles into those bilayer membranes. By placing a voltage gradient across the lipid bilayer and recording the transmembrane current, the activity of some membrane proteins, such as ion channels, can be analyzed. The methods permit access to a large variety of membrane proteins. The native vesicles may be derived from a variety of cells and intracellular organelles, and as the native cell membrane vesicles may be stored at low temperatures over long periods, the methods reduce the need to maintain cell cultures or obtain primary cells. Fluorescence measurements also may be performed on the bilayer membranes.

Abstract: A polymeric material which to form a stable, reproducible interface between the ionic and electronic domains of an ion selective sensor, or an ion selective field effect transistor, or the like is provided. When employed in an ion selective sensor, the polymeric material is advantageously provided over a solid internal reference electrode and an ion selective material is provided thereover. According to one embodiment, the polymeric material of the invention includes less than about 1.63×10<immobilized charged sites per gram (less than about 2.72 millaequivalents/gram). According to another embodiment, the polymeric material includes immobilized sites of charge opposite that of mobile ions involved in the redox couple. A preferred polymeric material comprises a copolymer of methacrylamidopropyltrimethylammoniumchloride and methylmethacrylate.

Abstract: A linker lipid for use in attaching a membrane including a plurality of ionophores to an electrode and providing a space between the membrane and the electrode in which the membrane is either in part or totally made up of the linker lipid. The linker lipid has within the same molecule a hydrophobic region capable of spanning the membrane, an attachment group used to attach the molecule to an electrode surface, a hydrophilic region intermediate the hydrophobic region and the attachment group, and a polar head group region attached to the hydrophobic region at a site remote from the hydrophilic region. The attachment group has a cross sectional area greater than the cross sectional area of the hydrophilic region, and has the structure recited in the specification.

Abstract: A sensor is provided that includes at least one functional coating layer that includes a UV-absorbing polymer. Methods for making the inventive sensors are also provided.

Abstract: A disposable plate electrode with biological active film is used to cooperate with a biological sensor for analyzing composition and measuring concentration of a test sample according to electric effect resulted from a biochemical reaction. The plate electrode comprises at least an electrode portion for transmission of the electric effect as well as a biological active film that reacts with the test sample chemically or biochemically. The biological active film contains a carrier layer (cellulose, for example) for adsorbing and keeping the biological active substance (enzyme, for example), which, the carrier layer, can change the electrode portion from hydrophobic into hydrophilic and protect the biological active substance against impairment during relatively higher temperature drying process.

Abstract: An improved combination ion-selective electrode apparatus is provided that comprises an electrode body, a reference electrode, and an ion-sensing electrode. The reference electrode comprises a ion-permeable junction. A removable membrane cap contains a ion-selective membrane. The membrane cap can be removed from the ion-selective electrode apparatus without endangering the integrity of the reference electrode and is distinct from the ion-permeable junction. The membrane cap contains a removable ion-sensitive membrane that can be replaced if the ion-sensitive membrane fails to thereby place the combination ion-selective electrode apparatus back into service. Moreover, a single combination ion-selective electrode apparatus can be used to measure a variety of analyte ions by simple replacement of the membrane cartridge.

Abstract: The present invention relates to a high through-put system for determining and/or monitoring electrophysiological properties of ion channels of ion channel-containing membranes, typically lipid membrane-containing structures such as cells. In particular, the invention provides a substrate which provides means for automatically positioning cells at measuring sites using electroosmotic flow in canals formed on or in the substrate. The electroosmotic flow is generated and controlled by electroosmotic flow pumps integrated on the substrate or positioned in relation thereto. Thereby, cells can be positioned in favorable measurement configuration at a plurality of sites for performing testing and measurements. Also, the invention relates to a main electric circuit for performing testing and measurements on a plurality of cells in parallel.

Abstract: An ion exchange membrane for use in sensors which measure dissolved gases. Disclosed is a method for using ion exchangers in gas permeable membranes to maintain optimal conditions in the electrolyte contained within the sensor. This can greatly extend the lifetime and improve the stability relative to sensors of similar size and electrolyte volume that have been constructed using prior art.

Abstract: The invention pertains to a novel ionophore having the general structure: wherein R1, R2, R3 and R4 are independently straight or branched chain alkyl having 4 to 12 carbon atoms or the alkyl groups may optionally contain a cycloalkyl group having 3 to 8 carbon atoms or R1 and R2 or R3 and R4 together with N to which they are attached, can form a ring having 5 to 8 carbon atoms. This ionophore has increased selectivity for carbonate ions over other ions, especially salicylate. The invention includes membranes containing effective amounts of the novel ionophores and -sensors containing these membranes.

Abstract: A membrane for use in a sensor having a detection arrangement. The membrane is of a cellulosic material incorporating a hydrophobic agent (e.g. isopropyl myristate) and is permeable by diffusion to an analyte species of interest to be detected directly or indirectly by the detection arrangement.

Abstract: The present invention relates to solid-state ion selective electrodes (ISEs), methods of producing same and devices containing same. The electrodes include: (a) an internal reference element which includes a homogenous conducting body; (b) a solid contact which includes a hydrophobic polymer, an ionophore and particles of conductive material and (c) an ion selective membrane which includes a hydrophobic polymer and an ionophore. The particles of conductive material are dispersed throughout the hydrophobic polymer of the solid contact.

Abstract: Sensor systems and sensing methods for detecting one or more analytes in a fluid. A sensor includes a polymer capable of undergoing a proton-coupled redox reaction. The polymer includes a plurality of reactive substituents capable of undergoing a reaction with an analyte. Upon exposure of the sensor to a fluid containing the analyte, a response is detected based on a change in the pKa of the polymer.

Abstract: The present invention provides a means to substantially decrease the pH bias that is commonly observed with pH data obtained using ion selective electrode (ISE) containing instruments that have a solvent polymeric membrane based ISE pH electrode. The pH bias is reduced by utilizing the discovery that the presence of protein in a liquid sample induces an apparent interference with the pH value.

Abstract: The present invention provides a biosensor for use in detecting the presence of an enzyme or enzymes in a sample. The biosensor comprises a membrane and means for determining the impedance of the membrane. The membrane includes ionophores therein to which are attached linkers. The linkers are cleavable by the enzyme or enzymes to be detected, with the cleavage of the linker causing a change in the ability of ions to pass through the membrane via the ionophores.

Abstract: Electrode membrane combinations for use in biosensors to detect analytes in a sample and methods for making and storing same are disclosed. In one aspect, a method is provided for producing a first layer electrode membrane comprising: (1) Forming a solution containing Linker Lipid A, the disulfide of mercaptoacetic acid (MAAD) or similar molecule, linker Gramicidin B, membrane spanning lipid C (MSL-C) and membrane spanning lipid D (MSL-D) or other suitable linker molecules and other ion channel combinations; (2) Contacting an electrode containing a clean gold surface with the solution, the disulfide containing components in the solution thus adsorbing onto the gold surface of the electrode; (3) Rinsing the electrode with a suitable organic solvent; and (4) Removing the excess organic solvent used for rinsing.

Abstract: Magnetic composites exhibit distinct flux properties due to gradient interfaces. The composites can be used to improve fuel cells and effect transport and separation of different species of materials. A variety of devices can be made utilizing the composites including a separator, a cell, an electrode for channeling flux of magnetic species, an electrode for effecting electrolysis of magnetic species, a system for channeling electrolyte species, a system for separating particles with different magnetic susceptibilities. Some composites can be used to make a dual sensor for distinguishing between two species of materials and a flux switch to regulate the flow of a redox species and a flux switch to regulate the flow of a chemical species. Some composites can control chemical species transport and distribution.

Abstract: An ion sensor and an ion sensor plate provided with an ion sensitive membrane which is characterized in that the ion sensitive membrane contains a material constituting the dissociation equilibrium of Ag/X, and an excessive quantity of an ion sensitive material or an anion scavenger. A coated film of surfactant is provided at the inner face of the passageway communicating with the test liquid-measuring electrode so as to add the surfactant to the test liquid. The plasticizer is added at a ratio of 65 to 80% by weight. The atomic ratio of silver and halogen in the silver halide layer is set to at least 1.2. The particle diameter of the modified silver halide layer is set to at most 1 &mgr;m.

Abstract: A polymeric material which to form a stable, reproducible interface between the ionic and electronic domains of an ion selective sensor, or an ion selective field effect transistor, or the like is provided. When employed in an ion selective sensor, the polymeric material is advantageously provided over a solid internal reference electrode and an ion selective material is provided thereover. According to one embodiment, the polymeric material of the invention includes less than about 1.63×10<immobilized charged sites per gram (less than about 2.72 millaequivalents/gram). According to another embodiment, the polymeric material includes immobilized sites of charge opposite that of mobile ions involved in the redox couple. A preferred polymeric material comprises a copolymer of methacrylamidopropyltrimethylammoniumchloride and methylmethacrylate.

Abstract: An apparatus and a method of characterising liquids employ liquid sensors of different types of technology, in order to generate characterisation data from the whole of the output signals originating from these sensors when they are soaked in a sample of the liquid. The set of sensors may comprise: lipid sensors, quartz microbalances, ion-selective electrodes, biosensors, chemical microelectrodes or even, in certain particular applications, fiber optic based-sensors. The output signals originating from the different sensors are normalized with respect to values which are determined in a prior standardization operation during which the sensors were soaked in at least one sample reference liquid.

Abstract: The invention concerns a sampling system and a process for its production. Such systems can easily be employed throughout in chemical and biochemical analysis. The sampling system should be simply constructed and universally usable alone and in combination and fabricable with little effort. The sampling system constructed as per the invention for analytes which are fluid or are contained in fluids consists of a planar support with various holes in it through which the particular fluid can pass into a channel which it subsequently exits. The channel is at least partly covered by a cover over the side opposite the support. In addition, a membrane pervious to the analyte is inserted which at least partly covers the channel on its open upper side. The areas not covered by the cover can be used to extract the analyte or to make direct measurements.

Abstract: An electrochemical affinity assay system for detection of ligand—ligand receptor binding.

Abstract: On an insulating substrate 1 is formed an electrode 2 as a working electrode, on which is formed a binding layer 3 mainly consisting of &ggr;-aminopropyltriethoxysilane. On the binding layer are sequentially formed an immobilized enzyme layer 4 in which a catalytic enzyme is immobilized in an organic polymer and a permeation restricting layer 5.

Abstract: A polymeric material which to form a stable, reproducible interface between the ionic and electronic domains of an ion selective sensor, or an ion selective field effect transistor, or the like is provided. When employed in an ion selective sensor, the polymeric material is advantageously provided over a solid internal reference electrode and an ion selective material is provided thereover. According to one embodiment, the polymeric material of the invention includes less than about 1.63×1021 immobilized charged sites per gram (less than about 2.72 millaequivalents/gram). According to another embodiment, the polymeric material includes immobilized sites of charge opposite that of mobile ions involved in the redox couple. A preferred polymeric material comprises a copolymer of methacrylamidopropyltrimethylammoniumchloride and methylmethacrylate.

Abstract: A micro-circuit for performing analyses of multimolecular interactions and for performing molecular syntheses, comprising: (a) a support; (b) at least one micro-electrode attached to the support, the micro-electrode being selectively electronically activated and the micro-electrode having a protective layer which is removable; (c) a binding entity for attachment to the at least one micro-electrode, the binding entity being capable of attachment to at least one micro-electrode when the protective layer has been removed; and (d) a power source being operatively connected to at least one micro-electrode for electronically activating at least one micro-electrode. The micro-circuit of the present invention also includes embodiments featuring a micro-circuit reader for detecting the interaction of the binding entity to a complementary probe, as well as methods for making and using the micro-circuit of the present invention.

Abstract: The invention concerns a cation-selective sensor provided with a cation-selective coating and based on the fact that analyte ions present in a solution cause detectable changes in the electrical characteristics of the layer. The acid/base components in the cation-selective layer render the sensor function independent of the anions present in the analyte solution. This improves the measurement accuracy and lowers the detection threshold.

Abstract: A blood analyzer sensor cartridge comprises a housing having chamber and a sensor assembly within the chamber, a first fluid port having an articulated inlet aspiration tube for direct introduction of a sample, a first fluid path in the housing communicating the first fluid port with the sensor assembly, a second fluid port in the housing adapted for connection to an analyzer, and a second fluid path in the housing communicating the sensor assembly with the second fluid port, the articulated tube is pivotally mounted to the housing for selective orientation within a range of up to ninety degrees, the tube is moveable from a protective recess in the housing to a position normal to a face of the housing.

Abstract: This invention relates to biologically-active polymers that are useful for analyte detection and isolation and delivery of substances. The biologically-active polymers are capable of specifically and reversibly binding to analytes, including molecules and cells. The biologically-active polymers are also capable of releasing substances upon electrical stimulation. The present invention provides compositions comprising biologically-active polymer membranes and methods for making these biologically-active polymer membranes that may be specifically designed to selectively bind cells and specific cell types, to affect cell growth characteristics, and to modulate cellular differentiation. These biologically-active polymer membranes may be controlled electrically to induce controlled cellular differentiation and modulate the cell growth cycle. These biologically-active polymers have many applications in biological and chemical fields.

Abstract: The present invention concerns a membrane electrode for measuring glucose concentration in liquids, comprising: a base membrane with at least one noble metal electrode which is arranged on one side of the base membrane; a proton-selective ion membrane arranged on the base membrane and the noble metal electrode; and a double membrane which is arranged on the ion membrane and in which glucose oxidase is contained in a suitable medium, and also an electronic circuit for operation of the membrane electrode comprising: a stabilised polarisation voltage source; two high-impedance amplifiers; a parallel resistor; an element for processing and storage of the measured parameter; and an output means.

Abstract: The present invention is a sensor formed over a subminiature through hole. Because of the small diameter of the through hole, the material that fills the through hole and the through hole itself have an essentially negligible effect on the sensor. Only a small amount of conductive material which fills each through hole is in contact with each associated electrode. Therefore, the purity of the electrode is not significantly altered by the conductive material coupled to the electrode. A relatively large number of sensors can be formed on the surface of the substrate within a relatively small fluid flowcell. Thus, more information can be attained using less blood. The sensors of the present invention are preferably disposed on an alumina substrate which is essentially impervious to aqueous electrolytes and blood over long periods of storage in potentially corrosive environments.

Abstract: A pH sensitive microsensor which comprises a substrate on which a sensor membrane is formed by laser ablation of a target and depositing the target material on the substrate.

Abstract: A new type of ion-selective solvent polymeric or liquid membrane electrode is constructed which allows to extend the measuring range at the lower end by at least six (6) orders of magnitudes. The new method can be used with membranes based on a neutral ionophore, a charged ionophore, or an ion-exchanger. Low detection limits are achieved by maintaining a very low and constant concentration of the primary ion and a sufficiently high concentration of an interfering ion in the internal reference solution. The low and constant concentration of the primary ion is either adjusted with the help of a solution of a hydrophilic ion buffer such as ethylenediamine tetraacetic acid or by adding an excess of a salt of an ion which forms a sparingly soluble salt with the primary ion, such as NaI for the primary ion Ag.sup.+. With the new technique, ion-selective electrodes can be used, for the first time, for environmental monitoring of heavy metal ions such as Pb.sup.2+ and Cd.sup.2+ at the submicromolar level.

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.