5389results about "Weather/light/corrosion resistance" patented technology

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.

An electrochemical assay includes a method for determining with great accuracy the time at which an applied sample bridges a gap between the electrodes of an electrochemical cell. The method involves applying a constant small current across the gap, while monitoring the potential difference between the electrodes. The time at which the sample bridges the gap is marked by a sharp drop in the potential. A constant voltage is applied after the sample is detected, and the current and/or charge through the sample is monitored over a period of time. From the measured current or charge, the analyte concentration of interest can be calculated.

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.

The invention is directed to apparatus and methods for delivering multiple reagents to, and monitoring, a plurality of analytical reactions carried out on a large-scale array of electronic sensors underminimal noise conditions. In one aspect, the invention provides method of improving signal-to-noise ratios of output signals from the electronic sensors sensing analytes or reaction byproducts by subtracting an average of output signals measured from neighboring sensors where analyte or reaction byproducts are absent. In other aspects, the invention provides an array of electronic sensors integrated with a microwell array for confining analytes and/or particles for analytical reactions and a method for identifying microwells containing analytes and/or particles by passing a sensor-active reagent over the array and correlating sensor response times to the presence or absence of analytes or particles. Such detection of analyte- or particle-containing microwells may be used as a step in additional noise reduction methods.

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 indicative of the diffusion coefficient and/or of the concentration of the reduced form (or the oxidised form) of the species. Also disclosed is an apparatus for determining the concentration of a redox species in an electrochemical cell comprising: an electrochemical cell having a working electrode and a counter (or counter/reference) electrode, means for applying and electric potential difference between said electrodes, means for measuring the change in current with time, and characterised in that the working electrode is spaced from the counter electrode by less than 500 mum.

The present invention relates generally to systems and methods for electrochemical sensing. Particularly, the invention relates to optimizing bias settings in an electrode system to increase oxygen production at the working electrode.

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.

In vitro electrochemical sensors that provide accurate and repeatable analysis of a sample of biological fluid are provided. Embodiments include sensors that include a sample chambers having overhangs extending therefrom.

Specific ionic interactions with a sensing material that is electrically coupled with the floating gate of a floating gate-based ion sensitive field effect transistor (FGISFET) may be used to sense a target material. For example, an FGISFET can use (e.g., previously demonstrated) ionic interaction-based sensing techniques with the floating gate of floating gate field effect transistors. The floating gate can serves as a probe and an interface to convert chemical and/or biological signals to electrical signals, which can be measured by monitoring the change in the device's threshold voltage, V_T.

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.

An improvement is described to disposable devices for performing chemical or biological tests on a sample of fluid, and the method by which such devices perform tests. The power for the device comes from an electrochemical battery, where a portion of the fluid sample itself provides the electrolyte for the battery. Furthermore, the time of diffusion of the fluid into the battery provides the timing signal for activation of the system. Communication between the improved device and an information system is provided by a transponder system built into the device which requires no direct electrical connection. Rather, the device is placed in proximity with a reader which can interrogate the device, obtain the results of the test and if necessary provide power for the device to perform the test, and/or communicate the information. The improvements and methods are particularly applicable to devices for performing in vitro diagnostic tests on a sample of body fluid.

Methods and devices for determining the concentration of an analyte in a physiological sample are provided which correct for errors in the analyte concentration measurement which are due to the hematocrit of the sample.

In vitro electrochemical sensor that provide accurate and repeatable analysis of a sample of biological fluid are provided. In some embodiments, the sensors have a measurement zone that has a volume less than the volume of the sample chamber. The measurement zone could have a volume of no more than about 0.2 μL.

Methods and apparatus relating to very large scale FET arrays for analyte measurements. ChemFET (e.g., ISFET) arrays may be fabricated using conventional CMOS processing techniques based on improved FET pixel and array designs that increase measurement sensitivity and accuracy, and at the same time facilitate significantly small pixel sizes and dense arrays. Improved array control techniques provide for rapid data acquisition from large and dense arrays. Such arrays may be employed to detect a presence and/or concentration changes of various analyte types in a wide variety of chemical and/or biological processes. In one example, chemFET arrays facilitate DNA sequencing techniques based on monitoring changes in the concentration of inorganic pyrophosphate (PPi), hydrogen ions, and nucleotide triphosphates.

Disclosed herein are methods and apparatus for determining analyte concentration in a rapid and accurate manner. The methods include depositing a physiological sample in an electrochemical cell and finding a first and second current transient. Peak current values are obtained from the first and second peak current values and used to reduce the influence of interferents in a current value. Based on this “corrected” current value, an accurate analyte concentration can be determined.

Provided are an apparatus and method for detecting biomolecules. The apparatus includes a FET having a substrate, a source electrode, a drain electrode, a channel region between the source and drain electrodes, and probe molecules fixed to the channel region, wherein the source and drain electrodes are separated on the substrate, a microfluid supplier selectively supplying one of a reference buffer solution of low ionic concentration and a reaction solution of high ionic concentration containing target molecules, to the channel region of the FET to which the probe molecules are fixed, and a biomolecule detector detecting the target molecules by measuring a first current value of the channel region of the FET, and a second current value of the channel region of the FET to which the target molecules and the probe molecules that bind to each other in the reaction solution of high ionic concentration are fixed.

The present invention provides a test strip for measuring a concentration of an analyte of interest in a biological fluid, wherein the test strip may be encoded with information that can be read by a test meter into which the test strip is inserted.

A glucose sensor system comprising the steps of using as a sample discriminating parameter a ratio (I/ΔI) of a measured current value I to the time-differential value of the current value ΔI, defining a discrimination function that discriminates whether a sample is blood or control fluid and uses the discriminating parameter as an independent variable, quantitating as a discriminating index a numeric value obtained by substituting a discriminating parameter value into this discrimination function, and automatically discriminating, based on this index, whether the sample is blood or a control fluid, whereby a kind of the sample can be automatically quantitated by measuring electric current when a sensor system is used for quantitating the concentration of an analysis object in the sample.

The presence of a select analyte in the sample is evaluated in an an electrochemical system using a conduction cell-type apparatus. A potential or current is generated between the two electrodes of the cell sufficient to bring about oxidation or reduction of the analyte or of a mediator in an analyte-detection redox system, thereby forming a chemical potential gradient of the analyte or mediator between the two electrodes After the gradient is established, the applied potential or current is discontinued and an analyte-independent signal is obtained from the relaxation of the chemical potential gradient. The analyte-independent signal is used to correct the analyte-dependent signal obtained during application of the potential or current. This correction allows an improved measurement of analyte concentration because it corrects for device-specific and test specific factors such as transport (mobility) of analyte and/or mediator, effective electrode area, and electrode spacing (and as a result, sample volume), without need for separate calibration values. The analysis can be performed using disposable test strips in a hand held meter, for example for glucose testing.

A wireless sensor system is installed inside pipelines using sensors and wireless transceivers that are small, low-cost, and rugged. The objective is monitoring the pipeline and recommending maintenance and repair at specific locations in the pipeline. Maintenance includes detection of leaks and prevention of catastrophic failures as a result of internal corrosion or other damage, such as third party mechanical damage, using multitude of sensors. After establishing the wireless sensor network the network is activated so the sensor can make measurements periodically or continuously using instructions transmitted via the base station. The sensor data from the various sensors are transmitted inside the pipe and extracted to access points in the pipeline to a remote computer that stores the data within the computer memory. The sensed information can be used for monitoring as well as analysis using a recommendation engine to provide maintenance and repair alerts.

A method of forming an electrical connection between an electrochemical cell and a meter is provided. According to the method, an electrical connection is made between a meter, by means of a wedge-shaped connector with upper and lower conductive surfaces, and an electrochemical cell comprising a first substrate with a first electrically conductive coating and a second substrate with a second electrically conductive coating, the electrically conductive coatings being disposed to face each other in a spaced apart relationship by an insulating spacer. The meter further includes a pivot point for rotating the wedge connector on the pivot point.

Described herein are wireless interrogation systems and methods that rely on a complementary sensing device and interrogator. The sensing device is disposed to measure a parameter indicative of the health of a structure. A sensor reading from the sensor indicates the level of a parameter being monitored or whether one or more particular physical or chemical events have taken place. Using wireless techniques, the interrogator probes the device to determine its identity and its current sensor reading. This often includes transmission of a wireless signal through portions of the structure. When activated, the device responds with a wireless signal that identifies the device and contains information about the parameter being measured or a particular sensor state corresponding to the parameter. The identity of the device allows it to be distinguished from a number of similar devices. Thus this invention finds particular usefulness in the context of an array of devices that can be probed by a wireless interrogation unit. In one embodiment, the devices are passive and derive power from the interrogation signal.

The present invention relates to electrochemical cells including a first working electrode 32, a first counter electrode 34, a second working electrode 36, and a second counter electrode 38, wherein the electrodes are spaced such that reaction products from the first counter electrode 34 arrive at the first working electrode 32, and reaction products from the first and second counter electrodes 34, 38 do not reach the second working electrode 36. Also provided is a method of using such electrochemical cells for determining the concentration of a reduced or oxidized form of a redox species with greater accuracy than can be obtained using an electrochemical cell having a single working and counter electrode.

Systems and methods are provided herein for improving the selectivity and productivity of sensors via digital signal processing techniques. According to one illustrative embodiment, in an electrochemical method for monitoring of a select analyte in a mixed sample with an interfering analyte, an improvement is provided that includes applying a large amplitude potential stimulus waveform to the sample to generate a nonlinear current signal; and resolving a signal contribution from the select analyte in the generated signal by a vector projection method with an analyte vector comprising a plurality of real and imaginary parts of one or more Fourier coefficients at one or more frequencies of a reference current signal for the select analyte.

A biosensor capable of measuring the concentration of one or more specific substances in one or more sample solutions almost simultaneously is provided. The biosensor comprises a plurality of sensor units, and each of the sensor units comprises an electrode system including a working electrode and a counter electrode on an insulating base plate and a reagent system including an oxidoreductase and an electron mediator. The biosensor is so configured that sample solutions supplied to the respective sensor units reach the respective reagent systems at different times. Specifically, each of the sensor units has a controlling system between a sample supply inlet and the reagent system, and the controlling system controls the time it takes for the sample solution to reach the reagent system from the sample supply inlet.

The present invention is related to an electrochemical biosensing test strip, biosensing meter, system and method for analyte measurement incorporating a hematocrit correction. The biosensor strip comprises a first and a second electrode sets respectively for detecting analyte concentration and hematocrit level. The first and second electrode sets are respectively corresponding to different reaction zones and a reaction reagent is only formed on the first electrode set corresponding reaction zone. Applying a first signal comprising a DC component and a second signal comprising an AC component that has a constant frequency respectively to the first and second electrode sets can respectively detect an uncorrected analyte concentration and hematocrit level. Therefore, the corrected analyte concentration is more accurate by incorporating the hematocrit correction.

An electrochemical sensor for analyzing a liquid sample, which is adapted to be connected with an electrochemical meter, comprises a channel for delivering the liquid sample; and a first conducting portion and a second conducting portion separated and exposed in the channel; wherein the first conducting portion generates a first pulse signal when it is contacted by the liquid sample, and the second conducting portion generates a second pulse signal when it is contacted by the liquid sample. The electrochemical meter obtains viscosity of the liquid sample according to a time difference between the first and second pulse signals.

An improved biosensor having at least a first working electrode and a first electrode material disposed on the first working electrode. The first electrode material is a mixture made by combining at least one enzyme where the at least one enzyme is a capable of reacting with the analyte to be measured, a redox mediator capable of reacting with a product of an enzymatic reaction or a series of enzymatic reactions involving the at least one enzyme, a peroxidase capable of catalyzing a reaction involving the redox mediator where the redox mediator is oxidized, a binder and a surfactant.

The invention belongs to the technical field of transformer ageing detection. An experimental device for transformer oilpaper insulating thermal ageing consists of an outer cavity, an inner cavity and a measurement-display system, wherein the inner cavity consist of a main cavity body, an oil conservator on the main cavity body, an electrode-sample test frame inside the main cavity body and a minor cavity body; the minor cavity body and the main cavity body are connected through a pipeline; a valve is arranged on the pipeline; and an air exhaust port and an oil injection port are arranged on the main cavity body. An experimental method for transformer oilpaper insulating thermal ageing comprises the following steps: 1) performing insulating-paperboard vacuum dry sample treatment; 2) placing sample and injecting oil; 3) installing the minor cavity body; 4) injecting transformer oil; 5) accelerating thermal ageing experiment; 6) measuring dielectric parameters on line to acquire related experiment data; and 7) analyzing off-line sample physicochemical parameters to acquire experiment data. The invention can measure the dielectric parameters of the samples on line in real time, regularly samples on the premise of not changing the prior test environment of the samples, and can research thermal ageing laws of oilpaper insulating materials of large-scale power transformers.

An electric sensor array which is provided with several sensor positions that each have at least two microelectrodes. Molecular substances can be detected electrochemically and charged molecules can be transported or handled using the array. Measuring procedures can be effected, especially using two addressing procedures, in which sensor positions can be individually addressed and electrochemically or electrically controlled by pairing or in groups for voltage or impedance measurements. For biomolecular assays, affinity-binding molecules can be immobilized at the sensor positions, between the microelectrodes, or on auxiliary surfaces.