5863 results about "Reference electrode" patented technology

An electrochemical analyte sensor having conductive traces on a substrate is used to determine a level of analyte in in vitro or in vivo analyte-containing fluids. The electrochemical analyte sensor includes a substrate and conductive material disposed on the substrate, the conductive material forming a working electrode. In some sensors, the conductive material is disposed in recessed channels formed in a surface of the sensor. An electron transfer agent and/or catalyst may be provided to facilitate the electrolysis of the analyte or of a second compound whose level depends on the level of the analyte. A potential is formed between the working electrode and a reference electrode or counter/reference electrode and the resulting current is a function of the concentration of the analyte in the fluid.

Devices and methods are provided for continuous measurement of an analyte concentration. The device can include a sensor having a plurality of sensor elements, each having at least one characteristic that is different from other sensor(s) of the device. In some embodiments, the plurality of sensor elements are each tuned to measure a different range of analyte concentration, thereby providing the device with the capability of achieving a substantially consistent level of measurement accuracy across a physiologically relevant range. In other embodiments, the device includes a plurality of sensor elements each tuned to measure during different time periods after insertion or implantation, thereby providing the sensor with the capability to continuously and accurately measure analyte concentrations across a wide range of time periods. For example, a sensor system 180 is provided having a first working electrode 150 comprising a first sensor element 102 and a second working electrode 160 comprising a second sensor element 104, and a reference electrode 108 for providing a reference value for measuring the working electrode potential of the sensor elements 102, 104.

An electrochemical immunosensor system with reduced interference, comprising: a first immunosensor that generates an electrochemical signal based on the formation of a sandwich between an immobilized antibody, a target analyte and a labeled antibody, wherein a portion of the signal arises from non-specific binding of the labeled antibody in the region of the first immunosensor, and a second immunosensor that acts as an immuno-reference sensor and generates a signal that is the same as or predictably related to the degree of non-specific binding which occurs in the region of the first immunosensor, and has an immunocomplex between an immobilized antibody and an endogenous or exogenous protein that is in the sample and that is not the target analyte.

A method of measuring an analyte concentration in body fluid in an animal body having skin and subcutaneous soft tissue that includes body fluid. The method comprises, introducing a portion of an analyte-measuring device into the subcutaneous soft tissue. The analyte-measuring device includes an analyte sensing element, having a sharpened distal end to facilitate introduction into the animal body. Additionally the sensing element has an indicating electrode that is adapted to be activated by electric power and to form a raw analyte measurement, when it is activated and in contact with the body fluid, in less than two minutes. The sensing device further has a reference electrode and an electric power and display device that is adapted to mate to the analyte-sensing element. The power and display device activates the analyte-sensing element by applying electric power to it. The analyte-sensing element is introduced into the animal body and is activated by the electric power and display device, thereby causing the analyte-sensing element to form a raw analyte measurement. The power and display device forms and displays a second analyte measurement that is related to the raw analyte measurement, within two minutes of the analyte sensing element being introduced into the body.

A biosensor in the form of a strip. In one embodiment, the biosensor strip comprises an electrode support, a first electrode, i.e., a working electrode, a second electrode, i.e., a counter electrode, and a third electrode, i.e., a reference electrode. Each of the electrodes is disposed on and supported by the electrode support. Each of the electrodes is spaced apart from the other two electrodes. The biosensor strip can include a covering layer, which defines an enclosed space over the electrodes. This enclosed space includes a zone where an analyte in the sample reacts with reagent(s) deposited at the working electrode. This zone is referred to as the reaction zone. The covering layer has an aperture for receiving a sample for introduction into the reaction zone. The biosensor strip can also include at least one layer of mesh interposed in the enclosed space between the covering layer and the electrodes in the reaction zone. This layer of mesh facilitates transporting of the sample to the electrodes in the reaction zone. In another embodiment, a biosensor strip can be constructed to provide a configuration that will allow the sample to be introduced to the reaction zone by action of capillary force. In this embodiment, the layer of mesh can be omitted. The invention also provides a method for determining the concentration of glucose in a sample of whole blood by using the biosensor of this invention.

The invention relates to apparatus and methods for measuring local tissue impedance for subcutaneous tissue surrounding a needle tip inserted into a subject, impedance spectra and/or complex impedance values are determined. The invention applies a monopolar impedance measuring setup with a needle, a current-carrying electrode, an optional reference electrode. The setup is configured to eliminate contributions from the current-carrying electrode in order to measure local impedance of tissue in the close neighbourhood of the needle tip instead of an averaged value over the volume or current path between the needle and the electrode(s). The determined impedance can be correlated with either a tissue type or state, or with a position of the needle tip in the subject, and can thereby provide an insertion history to the operator in the form of impedance or corresponding tissue type as a function of insertion depth or time.

Embodiments of the invention provide amperometric analyte sensors having multiple related structural elements (e.g. sensor arrays comprising a working, counter and reference electrode) and algorithms designed for use with such sensors. While embodiments of the innovation can be used in a variety of contexts, typical embodiments of the invention include glucose sensors used in the management of diabetes.

A disposable biosensor for testing a fluid sample including a laminated strip with a first and second end, a reference electrode embedded in the laminated strip proximate to the first end, at least one working electrode embedded in the laminated strip proximate to the first end and the reference electrode, an open path for receiving a fluid sample beginning from the first end and connecting to a vent spaced from the first end, the open path being sufficiently long to expose the reference electrode and the working electrode to the fluid sample, and conductive contacts located at the second end of the laminated strip. The laminated strip has a base layer with a conductive coating, a reagent holding layer, a channel forming layer and a cover having an inlet notch at the first end. The working electrode contains a reagent having an enzyme.

An analyte test sensor for use in measuring the concentration of a particular analyte in a test sample includes a non-conductive substrate, a reference electrode deposited on the substrate, a working electrode deposited on the substrate and a compensation electrode deposited on the substrate. The compensation electrode is provided with a resistive ladder and is designed to correct for test result inaccuracies which are the result of variances in the manufacturing of the test sensor. Specifically, in one embodiment, the compensation electrode corrects for test result inaccuracies in an analog manner by shunting a portion of the working current away from working electrode. In another embodiment, the compensation electrode corrects for test result inaccuracies in a digital manner by providing a calibration code which is proportional its resistance value. A batch of analyte test sensors are preferably manufactured in the following manner. An initial batch of the test sensors is constructed. Then, a limited sampling of the sensors is tested for accuracy using a control sample. Based on the test results, the resistance value of the compensation electrode for each remaining sensor in the batch is adjusted accordingly.

The disclosed electrochemical screening and early diagnostic device for malignant tumor comprises: an immune detection chip (1) connected to a time-resolution multichannel potentiostat (2) that connects to a data process and display system (3) by an interface. Wherein, the chip (1) comprises eight working electrodes fixed different antigen films and Ag wire (a), Ag/AgCl reference electrode (b), a carbon-pair electrode (c), and an insulation film (d). This invention needs low cost, has intelligence and fit to fast detection.

The present invention relates to an electronic circuit and an array of such circuits for precisely measuring small amounts or small changes in the amount of charge, voltage, or electrical currents. One embodiment of the present invention provides an electronic circuit for measuring current or charge that can be used with a variety of sensing media (including high impedance sensing media) that produce a signal by either charge or current production or induction in response to physical phenomena occurring within the sensing media. In another embodiment, the voltage level (bias) of either the sensing or reference electrode can be switched relative to the other upon receipt of a triggering pulse. This changes the polarity of the electric field to cause charge of the opposite polarity to be driven to the sensing electrode, thereby eliminating the need to electrically connect a discharge path to the sensing electrode to clear the charge accumulated at the sensing electrode. This can be supplemented by capacitively coupling a compensation signal to the sensing electrode to cause the amplifier output signal to lessen in magnitude below a threshold level that permits additional charge or current measurements of the same polarity before performing bias reversal. Alternately or in combination with bias reversal and capacitive compensation, sensor performance can be improved by minimizing inaccuracies caused by leakage currents or current drawn from the sensor. Other described methods of reducing leakage currents that can be used alone or in combination with the aforementioned features include the use of guard rings, physical switches or relays, the controlled creation of charges or currents of a specific polarity in a specific region of the sensing medium, controlled leakage over the surface of an insulator, and controlling the environment in which the circuit operates.

A biosensor for detecting contents of biochemical components in a sample, comprising an electrically insulating substrate, a working electrode disposed on said substrate, a reference electrode disposed on said substrate, which is spaced from said working electrode, a reaction layer disposed on said working electrode and said reference electrode, wherein said reaction layer and said electrodes form a reaction area for reacting with the sample, an electrically insulating layer disposed on said substrate and having an opening for receiving the sample, wherein said opening exposes a portion of said reaction area and the end of said opening is located at the edge of the biosensor; and a reticular covering layer which covers said opening and the end of said opening of said insulating layer wherein said reticular layer and said insulting layer form a sampling area from said reticular covering area to the edge of said biosensor.

A nanopost glass array contains up to 1012/cm2 of magnetizable nanoposts having diameter of 10-1000 nm that are straight and parallel to each other and are typically of a uniform diameter relative to each other and along the post length. The array is made using a reference electrode and a nanochannel glass template structure connected to each other electrically through an electrical source and both disposed in a plating solution. A magnetizable material is electroplated from the plating solution into the channels of the template structure.