5634results about "Material resistance" patented technology

Sensor platforms and methods of making them are described, and include platforms having horizontally oriented sensor elements comprising nanotubes or other nanostructures, such as nanowires. Under certain embodiments, a sensor element has an affinity for an analyte. Under certain embodiments, such a sensor element comprises one or more pristine nanotubes, and, under certain embodiments, it comprises derivatized or functionalized nanotubes. Under certain embodiments, a sensor is made by providing a support structure; providing a collection of nanotubes on the structure; defining a pattern within the nanotube collection; removing part of the collection so that a patterned collection remains to form a sensor element; and providing circuitry to electrically sense the sensor's electrical characterization. Under certain embodiments, the sensor element comprises pre-derivatized or pre-functionalized nanotubes. Under certain embodiments, sensor material is derivatized or functionalized after provision on the structure or after patterning. Under certain embodiments, a large-scale array includes multiple sensors.

The present invention relates to a wetness monitoring system that includes a data collection device that sends wetness measurement data to a central computer that detects changes in wetness measurement data caused by the presence of urine or other dielectric fluids. The data collection device includes a semi-reusable sensor and reusable data collector that are worn on a garment of the person. The data collector includes an internal power source so that the person can live a normal ambulatory life. The data collector has an electrical circuit that uses the changing resistance characteristics in the sensor to gather wetness measurement data. The data collector periodically generates and transmits a signal containing the actual wetness measurement data. The signals are coded to identify the particular data collector or person sending the signal. The data collector is programmed to conserve power by sending signals less frequently during periods when the sensor is clearly dry. Signals are sent more frequently when the sensor is damp or a wetness event may have occurred. The central computer receives the signals containing the wetness measurement data and compares the measurement data to an adjustable wetness sensitivity level to determine if a wetness event has occurred. When the central computer determines that a wetness event has occurred, the computer displays the name of the particular person wearing the data collector and the approximate time that the wetness event occurred. The system then pages an appropriate healthcare worker to inform them that the particular individual needs attention and tracks the approximate response times to ensure that the patient is continuously receiving prompt care.

A method and apparatus that use complex impedance measurements of tissue in human or animal bodies for the detection and characterization of medical pathologies is disclosed. An analysis of the complex impedance measurements is performed by a trained evaluation system that uses a nonlinear continuum model to analyze the resistive, capacitive, and inductive measurements collected from a plurality of sensing electrodes. The analysis of the impedance measurements results in the construction of a multidimensional space that defines the tissue characteristics, which the trained evaluation system uses to detect and characterize pathologies. The method and apparatus are sufficiently general to be applied to various types of human and animal tissues for the analysis of various types of medical pathologies.

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.

A method and apparatus are provided for correcting ambient temperature effect in biosensors. An ambient temperature value is measured. A sample is applied to the biosensors, then a current generated in the test sample is measured. An observed analyte concentration value is calculated from the current through a standard response curve. The observed analyte concentration is then modified utilizing the measured ambient temperature value to thereby increase the accuracy of the analyte determination. The analyte concentration value can be calculated by solving the following equation:where G1 is said observed analyte concentration value, T2 is said measured ambient temperature value and I1, I2, S1, and S2 are predetermined parameters.

A device, system and method for diagnosing and treating gastric disorders is provided. A functional device resides within the patient's stomach and is secured to the stomach wall by an attachment device. The functional device may be a sensor for sensing various parameters of the stomach or stomach environment, or may be a therapeutic delivery device. The functional device in one embodiment provides a device, system and method for gastric electrical stimulation where stimulating electrodes are secured to the wall of the stomach by the attachment device or otherwise. A preferred device includes: at least one stimulating electrode in electrical contact with the stomach wall; an electronics unit containing the electronic circuitry of the device; and an attachment mechanism for attaching the device to the stomach wall. The functional devices may be programmed to respond to sensed information or signals. An endoscopic delivery system delivers the functional device through the esophagus and into the stomach where it is attached the stomach wall. The endoscopic instruments attach or remove the attachment devices and functional devices from the stomach and may be used to assist in determining the optimal attachment location.

A method of forming a sensor for detecting gases and biochemical materials that can be fabricated at a temperature in a range from room temperature to 400° C., a metal oxide semiconductor field effect transistor (MOSFET)-based integrated circuit including the sensor, and a method of manufacturing the integrated circuit are provided. The integrated circuit includes a semiconductor substrate. The sensor for detecting gases and biochemical materials includes a pair of electrodes formed on a first region of the semiconductor substrate, and a metal oxide nano structure layer formed on surfaces of the pair electrodes. A heater is formed to perform thermal treatment to re-use the material detected in the metal oxide nano structure layer. Also, a signal processor is formed by a MOSFET to process a predetermined signal obtained from a quantity change of a current flowing through the pair of electrodes of the sensor. To form the sensor, the metal oxide nano structure layer is formed on surfaces of the pair of electrodes at a temperature in a range from room temperature to 400° C.

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.

A moisture sensor system is described. In one embodiment, the system provides an adjustable threshold level for the sensed moisture level. The adjustable threshold allows the moisture sensor to adjust to ambient conditions, aging of components, and other operational variations while still providing a relatively sensitive detection capability. In one embodiment, the adjustable threshold moisture sensor is used in an intelligent sensor system that includes one or more intelligent sensor units and a base unit that can communicate with the moisture sensor units. When one or more of the moisture sensor units detects a excess moisture the moisture sensor unit communicates with the base unit and provides data regarding the moisture condition. The base unit can contact a supervisor or other responsible person by a plurality of techniques, such as, telephone, pager, cellular telephone, Internet (and/or local area network), etc. In one embodiment, one or more wireless repeaters are used between the moisture sensor units and the base unit to extend the range of the system and to allow the base unit to communicate with a larger number of sensors.

Methods and devices are provided for characterizing a duplex nucleic acid, e.g., a duplex DNA molecule. In the subject methods, a fluid conducting medium that includes a duplex nucleic acid molecule is contacted with a nanopore under the influence of an applied electric field and the resulting changes in current through the nanopore caused by the duplex nucleic acid molecule are monitored. The observed changes in current through the nanopore are then employed as a set of data values to characterize the duplex nucleic acid, where the set of data values may be employed in raw form or manipulated, e.g., into a current blockade profile. Also provided are nanopore devices for practicing the subject methods, where the subject nanopore devices are characterized by the presence of an algorithm which directs a processing means to employ monitored changes in current through a nanopore to characterize a duplex nucleic acid molecule responsible for the current changes. The subject methods and devices find use in a variety of applications, including, among other applications, the identification of an analyte duplex DNA molecule in a sample, the specific base sequence at a single nulceotide polymorphism (SNP), and the sequencing of duplex DNA molecules.

A method of measuring an analyte in a biological fluid comprises applying an excitation signal having a DC component and an AC component. The AC and DC responses are measured; a corrected DC response is determined using the AC response; and a concentration of the analyte is determined based upon the corrected DC response. Other methods and devices are disclosed.

The present invention relates to an analyzing implement (1) having a capillary for movement of a specimen liquid. The capillary has inner surfaces (21c, 32c) provided with a first and a second opposed electrodes opposed to each other. The implement (1) includes, for example, a substrate (20), a cover (40) and a spacer (30) between the substrate (20) and the cover (40). In this case, the capillary is provided by the substrate (20), the cover (40) and the spacer (30). Preferably, capillary forming surfaces (31c, 32c) of the spacer (30) are electrically conductive, in which case the surfaces (31c, 32c) provide the first and the second electrodes.

Described herein are devices, systems, and methods for determining the composition of fluids, and particularly for describing the identity and concentration of one or more components of a medical fluid such as intravenous fluid. These devices, systems and methods take multiple complex admittance measurements from a fluid sample in order to identify the identity and the concentration of components of the fluid. The identity and concentration of all of the components of the solution may be simultaneously and rapidly determined. In some variations, additional measurement or sensing modalities may be used in addition to admittance spectroscopy, including optical, thermal, chemical, etc.

Sensor for detecting a physical or chemical quantity, comprising a defect controlled nanotube. The sensor can be produced by post treating a nanotube with sufficient energy to modify at least one of density and type of defects in the nanotube, and associating the nanotube with a circuit capable of providing an output signal based upon change of electrical characteristic of the nanotube in response to stimulus of the nanotube.

The present invention is directed to the development of a biosensor based on the immuno-chromatographic method that can provide an assay speed and convenience required for point-of-care (the doctor's office and emergency room) testing or home-version diagnosis. Though certain physical symptoms, such as pregnancy and ovulation, or bacterial infection may be identified by a qualitative analysis for the presence of indicating substances, most analytes for clinical investigation demand their concentrations known in specimens. Therefore, the inventors of the present invention have developed a novel biosensor by combining the immuno-chromatographic method and the electric conductivity detection technology so that on-site quantitative determination at the points of care or at home may be carried out.

A chemical-sensing apparatus is formed from the combination of a chemical preconcentrator which sorbs and concentrates particular volatile organic chemicals (VOCs) and one or more chemiresistors that sense the VOCs after the preconcentrator has been triggered to release them in concentrated form. Use of the preconcentrator and chemiresistor(s) in combination allows the VOCs to be detected at lower concentration than would be possible using the chemiresistor(s) alone and further allows measurements to be made in a variety of fluids, including liquids (e.g. groundwater). Additionally, the apparatus provides a new mode of operation for sensing VOCs based on the measurement of decay time constants, and a method for background correction to improve measurement precision.

The present invention provides fluidic devices and systems that allow detection of analytes from a biological fluid. The methods and devices are particularly useful for providing point-of-care testing for a variety of medical applications.

A moister sensor, for measuring moister in a building without leaving visible scars to the building surface, is provided. The moister sensor includes a flexible carrier carrying an antenna for receiving EM-radiation between 9 kHz and 11 MHz and a resonant circuit including a moister reactive element. The moister reactive element includes a hygroscopic electrolyte arranged between a first and a second electrode, wherein the electrolyte in the presence of moister forms mobile ions and provides a complex impedance at least in response to the alternating voltage, which complex impedance varies with the moister content of the electrolyte.

The present invention provides methods for detecting the presence of an analyte indicative of various medical conditions, including halitosis, periodontal disease and other diseases are also disclosed.

A method of producing polymer/nanotube composites where the density and position of the nanotubes (11) within the composite ca be controlled. Carbon nanotubes (11) are grown from organometallic micropatterns. These periodic nanotube arrays are then incorporated into a polymer matrix (7) by deposing a curable polymer film on the as-grown tubes. This controlled method of producing free-standing nanotube/polymer composite films may be used to form nanosensor (3) which provide information regarding a physical condition of a material (20), such as an airplane chassis or wing, in contact with the nanosensor (3).

A sensor and method for detecting biological and chemical agents comprising metal interdigitized electrodes coated with hybrid polymer-based conducting film and an instrument for applying electrical voltage to the electrodes and registering the change in voltage. The hybrid film also comprises indicator biomolecules encapsulated within the film or attached to it. When these indicator biomolecules come in a contact with a biological and chemical agent, morphological changes occur in the film and electrical current flowing through the electrodes is modulated. The change in current indicates the presence of a biological and chemical agent and is registered.

A single chip wireless sensor (1) comprises a microcontroller (2) connected by a transmit/receive interface (3) to a wireless antenna (4). The microcontroller (2) is also connected to an 8 kB RAM (5), a USB interface (6), an RS232 interface (8), 64kB flash memory (9), and a 32 kHz crystal (10). The device (1) senses humidity and temperature, and a humidity sensor (11) is connected by an 18 bit ΣΔ A-to-D converter (12) to the microcontroller (2) and a temperature sensor (13) is connected by a 12 bit SAR A-to-D converter (14) to the microcontroller (2). The device (1) is an integrated chip manufactured in a single process in which both the electronics and sensor components are manufactured using standard CMOS processing techniques, applied to achieve both electronic and sensing components in an integrated process.

Apparatus for sensing and characterizing particles (e.g., blood cells or ceramic powders) suspended in a liquid medium comprises a conduit through which the particle suspension is caused to pass simultaneously with an electrical current. According to the invention, the interior wall of the conduit effectively varies in resistivity along the length of the conduit to define a delimited central region of high electrical resistivity which is smoothly contiguous on its opposing boundaries to uninsulated distal elements of lesser electrical resistivity. The delimited central region of the conduit functions as a Coulter volumeter conduit. The uninsulated distal elements of the conduit are made to have a dimension along the conduit wall which is at least equal to the axial extent of the effective ambit electric fields of a traditional Coulter volumeter conduit having a cross-sectional geometry identical to that of the delimited central region of high resistivity in the improved volumeter conduit. According to a preferred embodiment of the invention, the delimited central region of the improved volumeter conduit is defined by a traditional Coulter conduit wafer, i.e., a dielectric wafer containing a central circular conduit, and the distal elements of lesser resistivity are defined by uninsulated, electrically conductive, circular collars attached to opposite sides of the conduit wafer. The conduit in the conduit wafer and the openings in the conductive collars collectively form a hydrodynamically smooth volumeter conduit, in which the electric and hydrodynamic fields of the traditional volumeter conduit are advantageously amended in the manner above noted.

A method of using a sensor comprising a field effect transistor (FET) embedded in a nanopore includes placing the sensor in an electrolyte comprising at least one of biomolecules and deoxyribonucleic acid (DNA); placing an electrode in the electrolyte; applying a gate voltage in the sub-threshold regime to the electrode; applying a drain voltage to a drain of the FET; applying a source voltage to a source of the FET; detecting a change in a drain current in the sensor in response to the at least one of biomolecules and DNA passing through the nanopore.

As disclosed within, the present device is directed to a multi-well sample module having integrated impedance measuring electrodes (which allow for the generation of an electric field within each well and the measuring of the change in impedance of each of the well's contents) and an electrical connection scheme allowing simultaneous measurement of each well's change in impedance.

Presteralized manifolds are provided which are designed for sterile packaging and single-use approaches. Disposable tubing and flexible-wall containers are assembled via aseptic connectors. These manifolds interact with valves and pumping equipment which can be operated by a controller which provides automated and accurate delivery of biotechnology fluid. The manifold also being used in conjunction with one or more conductivity sensors used to measure the conductivity of the biotechnology fluid. Such sensors interact with the controller or are connected to a separate user interface. The combination of disposable tubing, flexible-wall containers, aseptic connectors, manifold, controller, and conductivity sensors provides an aseptic environment while avoiding or reducing cleaning and quality assurance procedures.

The present invention provides a class of sensors prepared from at least a first material having a positive temperature coefficient of resistance and a second non-conductive or insulating material compositionally different than the first material that show an increase sensitivity detection limit for polar and non-polar analytes. The sensors have applications in the detection of analytes in the environment, associated with diseases and microorganisms.

A device for monitoring the migration or invasion of a biological particle such as a cell is disclosed. The device includes an upper chamber adapted to receive and retain a cell sample, a lower chamber having at least two electrodes, and a biocompatible porous membrane having a porosity sufficient to allow cells to migrate therethrough. The membrane is disposed in the device so as to separate the upper and lower chambers from one another. Migration of cells through the porous membrane permits contact between the migrating cells and one or more electrodes of the lower chamber. The contact provides a detectable change in impedance between or among the electrodes.

A device and method for sensing fluid characteristics, including, temperature, pH and chemistry, comprises a switch affixed to or embedded in a container of a size, shape and density such that said container floats stable in said liquid sensors which measure and report other characteristics of the liquid, such as temperature, pH, viscosity, chemistry or biochemistry.

A hydrogen gas sensor and/or switch fabricated from arrays nanowires composed of metal or metal alloys that have stable metal hydride phases. The sensor and/or switch response times make it quite suitable for measuring the concentration of hydrogen in a flowing gas stream. The sensor and/or switch preferably operates by measuring the resistance of several metal nanowires arrayed in parallel in the presence of hydrogen gas. The nanowires preferably comprise gaps or break junctions that can function as a switch that closes in the presence of hydrogen gas. Consequently, the conductivity of the nanowires of the sensor and/or switch increases in the presence of hydrogen