11278results 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.

An analyte-measuring device, particularly an electrochemical sensor, is provided for measuring current values at multiple bias potential settings to assess the quality of the analyte measurement, identify interference in the signal, and calculate substantially interference-free analyte concentration measurements. The device and method are suitable for calculating substantially interference-free analyte concentration measurements when glucose is the analyte and acetaminophen is an interfering species.

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 of determining a corrected analyte concentration in view of some error source are provided herein. The methods can be utilized for the determination of various analytes and/or various sources of error. In one example, the method can be configured to determine a corrected glucose concentration in view of an extreme level of hematocrit found within the sample. In other embodiments, methods are provided for identifying various system errors and/or defects. For example, such errors can include partial-fill or double-fill situations, high track resistance, and/or sample leakage. Systems are also provided for determining a corrected analyte concentration and/or detecting some system error.

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.

A fluid infusion system as described herein includes a number of local “body network” devices, such as an infusion pump, a handheld monitor or controller, a physiological sensor, and a bedside or hospital monitor. The body network devices can be configured to support communication of status data, physiological information, alerts, control signals, and other information between one another. In addition, the body network devices can be configured to support networked communication of status data, physiological information, alerts, control signals, and other information between the body network devices and “external” devices, systems, or communication networks. The networked medical devices are configured to support a variety of wireless data communication protocols for efficient communication of data within the medical device network. In addition, the wireless medical devices may be configured to support a number of dynamically adjustable wireless data communication modes to react to current operating conditions, application-specific data content, or other criteria.

<heading lvl="0">Abstract of Disclosure</heading> A small volume sensor, and methods of making, for determining the concentration of an analyte, such as glucose or lactate, in a biological fluid, such as blood or serum, using techniques such as coulometry, amperometry, and potentiometry. The sensor includes a working electrode and a counter electrode, and can include an insertion monitoring trace to determine correct positioning of the sensor in a connector.