Abstract: The present invention includes a magnetically susceptible polymer component, a method of making the same, and apparatuses and systems for mixing, separating or localizing a magnetically susceptible polymer compound in a reaction. The magnetically susceptible polymer component includes a polymer and a magnetically susceptible particle of a predetermined size, which yields a component having a much-improved magnetic reactivity due to the increase in magnetic material by mass percentage. The apparatuses and systems of the present invention employ controllable magnetic fields distributable in perpendicular directions in order to precisely control the orientation, position and relative motion of any magnetically susceptible components within a reaction vessel.

Abstract: The present disclosure provides a biological field effect transistor (BioFET) device testing and processing methods, system and apparatus. A wafer-level bio-sensor processing tool includes a wafer stage, an integrated electro-microfluidic probe card, and a fluid supply and return. The integrated electro-microfluidic probe card includes a fluidic mount that may be transparent, a microfluidic channels in the fluidic mount, at least one microfluidic probe and a number of electronic probe tips at the bottom of the fluidic mount, fluidic and electronic input and output ports on the sides of the fluidic mount, and at least one handle lug on the fluidic mount. The method includes aligning a wafer, mounting the integrated electro-microfluidic probe card, flowing a test fluid, and measuring electrical properties. The tool may also be used for stamping or printing a fluid in the device area on the wafer.

Abstract: An electrofluidic device includes first structural layer and second structural layer. First structural layer includes first substrate; and first electrode and second electrode on the first substrate. The second electrode has an indent region surrounding and without contacting first electrode. First hydrophobic layer is at least over the second electrode. Second structural layer at one side of the first structural layer with a gap includes second substrate and groove structure layer. The groove structure layer includes an indent groove, corresponding to the indent region of the second electrode. Second hydrophobic layer is over the groove structure layer. Polar fluid is disposed in the indent groove and remains in contact with the first electrode. Non-polar fluid is disposed in the gap between the first and second structural layers.

Abstract: A microorganism number-measuring apparatus includes: measurement container including measurement liquid; rotary driver; bacteria-collection signal generator; measurement signal generator; output amplifier for amplifying outputs of signal generators and; I/V amplifier; impedance measuring unit for measuring impedance of liquid; microorganism number-computing unit for computing the number of microorganisms present in liquid; solution conductivity-computing unit for computing conductivity of liquid; and warm-up section for warming up at least one of I/V amplifier and output amplifier. Warm-up section computes a warm-up signal based on the conductivity computed by conductivity-computing unit. Warm-up section computes the warm-up signal having a current the same in magnitude as that flowing through measurement electrode by using the measured solution conductivity, and applies the signal to at least one of I/V amplifier and output amplifier.

Abstract: Methods and systems for measuring and using the oxidation-reduction characteristics of a biological sample are provided. The system generally includes a test strip and a readout device. A fluid sample is placed in the test strip, and the test strip is in turn operatively connected to the readout device. The readout device provides a controlled current that is sent across the fluid in the sample chamber. In addition, the readout device identifies an inflection point or transition time at which the voltage between contacts of the test strip is changing at the highest rate. The oxidation-reduction capacity of the sample is taken as the integral of the current profile from the time at which current begins to be supplied to the sample to the identified transition time.

Abstract: 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.

Abstract: The present invention relates to a method for manufacturing a micro wire, a sensor including the micro wire, and a method for manufacturing the sensor, having improved production efficiency. According to an embodiment of the present invention, a method for manufacturing a micro wire includes applying a three-dimensional electric field to a solution for forming a micro wire. The method for manufacturing the micro wire may further include providing an electrode assembly comprising a substrate, a first electrode and a second electrode formed on the substrate, and providing the solution to a space. The first electrode and the second electrode may form the space therebetween, and the space may have a first width and a second width that is smaller than the first width. The three-dimensional electric field is applied to the solution by applying a voltage to the first electrode and the second electrode.

Abstract: Method for transport of suspensions containing mechanically sensitive material with a sample-transporting device comprising transport conduits and at least one system for accelerating a sample or aliquot through the transport conduit from at least two burets.

Abstract: A microfluidic electrochemical device and process are detailed that provide chemical imaging and electrochemical analysis under vacuum at the surface of the electrode-sample or electrode-liquid interface in-situ. The electrochemical device allows investigation of various surface layers including diffuse layers at selected depths populated with, e.g., adsorbed molecules in which chemical transformation in electrolyte solutions occurs.

Abstract: The present invention relates to bead incubating and washing on a droplet actuator. Methods for incubating magnetically responsive beads that are labeled with primary antibody, a sample (i.e., analyte), and secondary reporter antibodies on a magnet, on and off a magnet, and completely off a magnet are provided. Also provided are methods for washing magnetically responsive beads using shape-assisted merging of droplets. Also provided are methods for shape-mediated splitting, transporting, and dispensing of a sample droplet that contains magnetically responsive beads. The apparatuses and methods of the invention provide for rapid time to result and optimum detection of an analyte in an immunoassay.

Abstract: The invention provides a method of redistributing magnetically responsive beads in a droplet. The method may include providing a droplet including magnetically responsive beads. The droplet may be provided within a region of a magnetic field having sufficient strength to attract the magnetically responsive beads to an edge of the droplet or towards an edge of the droplet, or otherwise regionalize or aggregate beads within the droplet. The method may also include conducting on a droplet operations surface one or more droplet operations using the droplet without removing the magnetically responsive beads from the region of the magnetic field. The droplet operations may in some cases be electrode-mediated. The droplet operations may redistribute and/or circulate the magnetically responsive beads within the droplet. In some cases, the droplet may include a sample droplet may include a target analyte.

Abstract: A new reaction apparatus including a capillary having an inner surface to which a probe molecule that specifically binds to an analyte is immobilized, allowing a short throughput time for completing the binding reaction, and achieving a highly efficient reaction using a small amount of a sample and a process of the reaction are provided. The reaction apparatus includes a capillary having an inner surface to which a probe molecule that specifically binds to an analyte is immobilized; a columnar magnetic body that is disposed in a fluid containing the analyte in the state that the fluid is placed in the capillary; end-fixing means for fixing one end of the columnar magnetic body in the capillary by a DC magnetic field; and end-moving means for moving the other end of the columnar magnetic body by an AC magnetic field so as to transfer the fluid.

Abstract: A hand-held test meter for use with an analytical test strip in the determination of an analyte in a bodily fluid sample includes a housing; a microcontroller block disposed in the housing; and a phase-shift-based hematocrit measurement block. The phase-shift-based hematocrit measurement block includes a signal generation sub-block, a low pass filter sub-block, an analytical test strip sample cell interface sub-block, a transimpedance amplifier sub-block, and a phase detector sub-block. In addition, the phase-shift-based hematocrit measurement block and microcontroller block are configured to measure the phase shift of a bodily fluid sample in a sample cell of an analytical test strip inserted in the hand-held test meter and the microcontroller block is configured to compute the hematocrit of the bodily fluid sample based on the measured phase shift.

Abstract: A method and device for merging and mixing at least two separate and distinct fluid drops on a substrate, includes a drop merging area on the surface, where a first magnetic material is placed at a first location. A first drop of fluid is then placed at the first location on the surface, resulting in the first magnetic material being at least partially positioned within the first drop of fluid. A second drop of fluid is then placed at a second location on the surface of the drop merging area. A magnetic field is applied by a varying magnetic field generator to at least a portion of the drop merge area of the substrate, which includes at least the first location on the substrate. The varying magnetic field will act on the first magnetic material to move the first magnetic material within the first drop of fluid, causing a stirring of the fluid. A drop merging force from a drop merging mechanism is applied to at least one of the first drop of fluid and the second drop of fluid within the drop merge area.

Abstract: An assembly for testing platelet aggregation including an electrode subassembly that is mounted in a cuvette subassembly for use with relatively small samples containing platelets.

Abstract: The present invention relates to droplet-based washing. According to one embodiment, a method of providing a droplet in contact with a surface with a reduced concentration of a substance is provided, wherein the method includes: (a) providing a surface in contact with a droplet comprising a starting concentration and starting quantity of the substance and having a starting volume; (b) conducting one or more droplet operations to merge a wash droplet with the droplet provided in step (a) to yield a combined droplet; and (c) conducting one or more droplet operations to divide the combined droplet to yield a set of droplets comprising: (i) a droplet in contact with the surface having a decreased concentration of the substance relative to the starting concentration; and (ii) a droplet which is separated from the surface.

Abstract: Sample processing units useful for mixing and purifying materials, such as fluidic materials are provided. A sample processing unit typically includes a container configured to contain a sample comprising magnetically responsive particles, and one or more magnets that are in substantially fixed positions relative to the container. A sample processing unit also generally includes a conveyance mechanism configured to convey the container to and from a position that is within magnetic communication with the magnet, e.g., such that magnetically responsive particles with captured analytes can be retained within the container when other materials are added to and/or removed from the container. Further, a sample processing unit also typically includes a rotational mechanism that is configured to rotate the container, e.g., to effect mixing of sample materials disposed within the container. Related carrier mechanisms, sample processing stations, systems, and methods are also provided.

Abstract: A cartridge device having a receiving portion for receiving a blood sample and a jack portion for receiving a plug; a stirring device for circulating the blood sample within the receiving portion; and an electrode holder having at least one incorporated electrode wire pair; wherein the electrode holder is attachable to the cell such that one end of the at least one electrode wire pair forms a sensor unit for measuring the electrical impedance between the two electrode wires of the at least one electrode wire pair within the blood sample and that the opposite end of the at least one electrode wire pair forms a plug portion being connectable directly to the plug for an electrical connection of the sensor unit to an analyzer.

Abstract: The present disclosure relates to various methods for measuring the amount of an analyte present in a biological fluid using an electrochemical testing process. Various embodiments are disclosed, including the use of AC test signals and the performance of tests having a Total Test Time within about 3.0 seconds or less, and/or having a clinically low Total System Error.

Abstract: Methods, systems, and computer readable media for using actuated surface-attached posts for assessing biofluid rheology are disclosed. According to one aspect, a method for testing properties of a biofluid specimen includes placing the specimen onto a micropost array having a plurality of microposts extending outwards from a substrate, wherein each micropost includes a proximal end attached to the substrate and a distal end opposite the proximal end, and generating an actuation force in proximity to the micropost array to actuate the microposts, thereby compelling at least some of the microposts to exhibit motion. The method further includes measuring the motion of at least one of the microposts in response to the actuation force and determining a property of the specimen based on the measured motion of the at least one micropost.

Abstract: A total organic carbon measuring instrument including a measuring unit composed of, integrated together, organic substance oxidation part and carbon dioxide separation part and conductivity measuring part, control unit and data processing unit. In order to enhance the accuracy of conductivity measurement, the control unit is constructed so as to stop feeding of a sample water at the time of oxidation of organic substance and carry out feeding of the sample water at the time of sample water moving to the organic substance oxidation decomposition part and carbon dioxide separation part. The data processing unit is constructed so as to measure the total organic carbon concentration on the basis of conductivity at the time of arriving of sample water irradiated with ultraviolet rays of which relative intensity is a given value or higher at the carbon dioxide separation part.

Abstract: A pair or receptacles capable of housing an emitter probe and a detector probe are installed inside a bioreactor to monitor the properties of the nutrient media without contacting the nutrient media.

Abstract: Provided is a detection method for a target substance capable of enhancing detection sensitivity and quantitative property of a magnetic biosensor, while keeping monodispersity and dispersion stability of magnetic markers, including the steps of: reacting the target substance in a sample solution with a first target substance trapping member immobilized on a sensing element and with a second target substance trapping member immobilized on a gel particle to hold the gel particle on the sensing element; adjusting a magnetic marker precursor including the gel particle and a magnetic material precursor existing in the gel particle by bringing the magnetic material precursor into contact with the gel particle; synthesizing a magnetic material from the magnetic material precursor held on the gel particle, thereby adjusting the magnetic markers; and detecting the magnetic markers with the sensing element.

Abstract: 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.

Abstract: Disclosed is a bubble excluder device (2) adapted for use with, and attachment to, a probe (6) for continuous measurement of the cell density of a culture in a liquid medium; the bubble excluder device comprising an inlet and an outlet to allow flow of liquid through the device and bubble exclusion means (20) to reduce or prevent ingress of bubbles from the liquid medium outside the device.

Abstract: 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.

Abstract: The present invention provides a chemiresistor-based sensor for measuring the presence or amount of analyte in an electrolyte solution; said chemiresistor comprising (i) a chemiresistor film wherein the impedance of said nanoparticle film changes in the presence of an analyte; and (ii) two electrically conducting electrodes in electrical contact with said nanoparticle film; wherein said electrically conducting electrodes are adapted to be connected to a device for measuring the impedance of said chemiresistor film under a voltage signal and wherein the impedance of the double layer capacitor formed by the two electrically conducting electrodes in the presence of the electrolyte solution, is larger than the impedance of the chemiresistor film either before or after exposure of the chemiresistor film to the analyte. A method of using said chemiresistor-based sensor to measure the presence or amount of analyte is also provided.

Abstract: A chemical sensor that works while being submerged in a highly conductive medium is described. The chemical sensor includes hydrophobic structures that are distributed on conductive electrodes and are separated by small air cavities while submerged in the conductive medium. The hydrophobic structures are arranged such that their hydrophobicity varies in response to exposure to a target analyte. The change in the level of hydrophobicity results in permeation of the conductive liquid on to the conductive electrodes, thereby reducing the resistance levels between the conductive electrodes. The sensor indicates presence of the target analyte in response to detection of a change in resistance between at least two of the conductive electrodes.

Abstract: The invention provides a method of circulating magnetically responsive beads within a droplet in a droplet actuator. The invention also provides methods for splitting droplets. The invention, in one embodiment, makes use of a droplet actuator with top and bottom substrates, a plurality of magnetic fields respectively present proximate the top and bottom substrates, wherein at least one of the magnet fields is selectively alterable, and a plurality of droplet operations electrodes positioned along at least one of the top and bottom surfaces. A droplet is positioned between the top and bottom surfaces and at least one of the magnetic fields is selectively altered.

Abstract: Methods and devices for conducting platelet aggregation analysis. A method for conducting platelet aggregation analysis by a cartridge device, including providing a blood sample in the cartridge device, stirring the blood sample within the cartridge device, measuring the electrical impedance between electrodes to obtain measured electrical impedance values, comparing measured electrical impedance values, discarding and repeating the measurements of the electrical impedance in case a variation of the measurements is outside a predetermined threshold range, or reporting the measured electrical impedance values in case the variation of the measurements is within the predetermined threshold range. Reported measured electrical impedance values indicate platelet aggregation in a blood sample.

Abstract: A reaction characteristic detector comprising a ladder assembly including a plurality of rungs, where each rung in the plurality of rungs comprises a reaction passage determiner spaced a distance from a point of an energetic material reaction initiation. Each reaction passage determiner has at least one characteristic that is configured to change in response to the reaction occurring proximate to the reaction passage determiner.

Abstract: A sensor instrument system for detecting and identifying analytes in fluids of a region contains a local sensor instrument and remote central station. The instrument includes a core technology employing a single sensor having two electrodes operated by an electrical frequency sweeping to generate two sets of patterned electrical information from a single measurement, a data transmission module and a GPS receiver module. The central station connects to a network means connected to a plurality of local receiving sites equipped with including the respective transceivers, so that the local analyte electrical information and geographic position information transmitted by the instrument can be wirelessly and remotely received and processed by the central station.

Abstract: A method and apparatus for near real-time in-situ soil solution measurements is presented. An outer sleeve is placed in soil where ionic concentrations of organic or inorganic species are to be measured. A porous section connects with the outer sleeve (the porous section initially loaded with distilled water) equilibrates with the solution present in soil pores to form a solution to be measured. The initial distilled water is displaced within the porous section by a removable plunger. After substantial equilibration of the solution to be measured within the apparatus, the plunger is removed and a removable probe replaced. The probe may be an Ion Selective Electrode, or a transflection dip probe. The probe then may be used under computer control for measurement of solution properties. The Ion Selective Electrode may measure nitrate (NO3?) concentrations. The transflection dip probe may be read with spectrometer with an input deuterium light source.

Abstract: A biosensor system determines analyte concentration from an output signal generated by an oxidation/reduction reaction of the analyte. The biosensor system adjusts a correlation for determining analyte concentrations from output signals at one temperature to determining analyte concentrations from output signals at other temperatures. The temperature-adjusted correlation between analyte concentrations and output signals at a reference temperature may be used to determine analyte concentrations from output signals at a sample temperature.

Abstract: Electronic devices comprising a dielectric material, at least one carbon sheet, and two electrode terminals are described herein. The devices exhibit non-linear current-versus-voltage response over a voltage sweep range in various embodiments. Uses of the electronic devices as two-terminal memory devices, logic units, and sensors are disclosed. Processes for making the electronic devices are disclosed. Methods for using the electronic devices in analytical methods are disclosed.

Abstract: An analyte concentration, in a sample fluid, is determined by differential measurement. Two or more capacitive field effect sensors have an identical basic structure and are arranged in a shared measuring cell. One of the sensors forms a measuring sensor with an active transductor layer. Another sensor forms a reference sensor without an active transductor layer. The sensors are contacted with the sample fluid and the sensors, have an associated reference electrode, or have a shared reference electrode. A bias voltage composed of an electric DC voltage and a superimposed AC voltage is applied between each sensor and associated reference electrode(s) Capacitance changes due to the analyte are eliminated by controlling the bias voltage applied to the measuring sensor in a closed control loop. A measuring signal is obtained by calculating a difference between voltage values representative of DC voltage potentials applied to the measuring sensor and reference sensor, respectively.

Abstract: System and method for capturing, concentrating, and detecting a diagnostic target in a liquid, comprising applying a magnetic field to a mixture comprising a co-aggregate in the liquid to provide a collected co-aggregate in the liquid, wherein the co-aggregate comprises a magnetic particle having a stimuli-responsive polymer attached thereto and a non-magnetic particle having a stimuli-responsive polymer and a diagnostic target attached thereto.

Abstract: The present disclosure relates to various methods for measuring the amount of an analyte present in a biological fluid using an electrochemical testing process. Various embodiments are disclosed, including the use of AC test signals and the performance of tests having a Total Test Time within about 3.0 seconds or less, and/or having a clinically low Total System Error.

Abstract: A method for analyzing hemoglobin in a sample by separation analysis while suppressing the denaturation of the hemoglobin includes separating hemoglobin in the presence of at least one of a sulfurous acid compound and a dithionous acid compound.

Abstract: A sensor-dispensing instrument adapted to handle a sensor pack contains sensors and performs a test using one of the sensors. The instrument includes an outer housing and a mechanical mechanism for rotating the sensor pack and ejecting one of the sensors from the sensor pack and through a sensor slot on the housing. The instrument also includes a sensor actuator to engage with a sensor disposed in the sensor slot, and a sensor release that is movable to disengage the sensor actuator from the sensor disposed in the sensor slot and permit the discharge of the sensor. The sensor release activates a sensor release mechanism that has a sensor release aid arm, a mounting block, and a pivot pin. The sensor release aid arm contacts the sensor disposed in the sensor slot to assist removal of the sensor from the sensor slot.

Abstract: A chemical sensor using metal nano-particles and a method for manufacturing a chemical sensor using metal nano-particles are provided. The chemical sensor includes: metal nano-particles; single-ligand organic molecules (or a single molecule) that binds to the metal nano-particles by using a metal bonding functional group; a substrate bonding functional group formed at the metal nano-particles and the single-ligand organic molecules as bound to each other; a substrate; electrodes formed on the substrate and having an interdigitate (IDT) structure; and a substrate functional group formed on the substrate and positioned between the electrodes, wherein the substrate bonding functional group and the substrate functional group are covalently bonded.

Abstract: A system for diagnostic testing may include a meter for performing a diagnostic test on a sample applied to a test media and a container configured to contain test media compatible with the meter. The meter may include a closure portion for selectively closing the opening of the container. The system may further provide a sampling device, such as a lancet, operable connected to the container such that that a user may use the sampling device to obtain a sample without disconnecting the sampling device from the container. The system may also provide mechanisms for removing a meter from a test container and reattaching it to a new one using one of several coding methods that recalibrate the meter for the new container of test strips. In addition, the system may further provide mechanisms to reconfigure the meter to perform a new function when it has been determined that the triggering event has occurred.

Abstract: A system for diagnostic testing may include a meter for performing a test on a sample applied to a test media and a selectively closable container configured to house test media compatible with the meter. The system may also provide mechanisms for removing a meter from a test container and reattaching it to a new one using one of several coding methods that recalibrate the meter for the new container of test strips. Alternatively, the system may include an auto-calibration system where data is provided individually on each individual test medium in a form readable by the test meter. The carried data may include an embedded code relating to data particular to that individual strip. The data is presented so as to be read by a meter associated with the diagnostic test strip in order to avoid manually inputting the information. In addition, the system may further provide mechanisms to reconfigure the meter to perform a new function when it has been determined that a triggering event has occurred.

Abstract: A new reaction apparatus including a capillary having an inner surface to which a probe molecule that specifically binds to an analyte is immobilized and achieving a highly efficient reaction using a small amount of a sample and a process of the reaction are provided. The reaction apparatus includes a capillary having an inner surface to which a probe molecule that specifically binds to an analyte is immobilized; a passage allowing a fluid discharged from one end of the capillary to flow to the other end of the capillary; a columnar magnetic body that is disposed in a fluid containing the analyte in the capillary and/or the passage in the state that the fluid fed in the capillary can circulate via the passage; end-fixing means for fixing one end of the columnar magnetic body in the capillary and/or the passage by a DC magnetic field; and end-moving means for moving the other end of the columnar magnetic body by an AC magnetic field such that the fluid circulates via the passage.

Abstract: 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.

Abstract: A method for the calibration of a device for measuring the total organic carbon content (TOC) of an aqueous solution by measuring resistivity. The method includes the following steps, in the presence of a reference TOC analyzer: (a) producing a calibration point by a measurement carried out on ultrapure water by the device and the analyzer; (b) producing a plurality of calibration points, each calibration point corresponding to a measurement of the resistivity of a solution having a given content of photo-oxidizable compound, by the device and the analyzer, in order to establish a correlation between the values measured by the device and the analyzer; and (c) calibrating the device by at least one algorithm, based on the measurements carried out in the previous step.

Abstract: A chemical analytic apparatus of the present invention is the one which proposes that a miniaturization, a making low-cost and portability are possible and also the operation of each process of separation, concentration and dilution of specimen is possible, and, which includes: an introduction means (S1) that introduces a droplet to which magnetic ultrafine particles are mixed into another liquid that differs from the droplet while maintaining a single droplet; a conveyance means by which the droplet that includes the magnetic particles is conveyed in another liquid of the introduction means by applying magnetic field externally to the magnetic ultrafine particles; and processing means (S2 to S6) by which operations for processing of chemical analysis are performed one by one in the process in which the droplet to which the magnetic ultrafine particles are mixed is conveyed by the conveyance means.

Abstract: According to various embodiments, a microfluidic system for detecting a biological entity in a sample volume is provided. The microfluidic system may include: a chamber configured to receive the sample volume, wherein the chamber includes a detection region for detecting the biological entity; a first port in fluid communication with the chamber; and a second port including a filter in fluid communication with the chamber; and wherein a fluid provided to the first port or the second port flows between the first port and the second port through the chamber.

Abstract: In accordance with the present invention there is provided a bi-stable oscillator circuit for detecting a load imparted to a surface. The bi-stable oscillator comprises an electrical amplifier, at least one resonator comprising an electrical transducer having a resonant frequency, a surface of the resonator forming the surface on which the load is to be detected and an impedance network having a resonant frequency.

Abstract: Provided are a FET-based sensor for detecting an ionic material, an ionic material detecting device including the FET-based sensor, and a method of detecting an ionic material using the FET-based sensor. The FET-based sensor includes: a sensing chamber including a reference electrode and a plurality of sensing FETs; and a reference chamber including a reference electrode and a plurality of reference FETs. The method includes: flowing a first solution into and out of the sensing chamber and the reference chamber of the FET-based sensor; flowing a second solution expected to contain an ionic material into and out of the sensing chamber while continuously flowing the first solution into and out of the reference chamber; measuring a current in a channel region between the source and drain of each of the sensing and reference FETs; and correcting the current of the sensing FETs.