Abstract: The present invention relates to methods of determining the concentration of an analyte in a sample or improving the performance of a concentration determination. The electrochemical sensor strips may include at most 8 ?g/mm2 of a mediator. The strips, the strip reagent layer, or the methods may provide for the determination of a concentration value having at least one of a stability bias of less than ±10% after storage at 50° C. for 4 weeks when compared to a comparison strip stored at ?20° C. for 4 weeks, a hematocrit bias of less than ±10% for whole blood samples including from 20 to 60% hematocrit, and an intercept to slope ratio of at most 20 mg/dL.

Abstract: The present invention relates to mutants of the Penicillium amagasakiense glucose oxidase (GOx) enzyme which are of use for assaying glucose and to the development in particular of glucose electrodes and of biocells which use glucose as fuel.

Abstract: Provided herein are isolated polypeptides comprising the amino-terminal domain of Mycobacterium tuberculosis porin A (MtpA), wherein the polypeptide is a porin monomer. Also provided are isolated polypeptides comprising the carboxy-terminal domain of Mycobacterium tuberculosis porin A, wherein the polypeptide is a toxin. Also provided are methods of treating or preventing a Mycobacterium tuberculosis (Mtb) infection in a subject with or at risk of developing a Mtb infection. Further provided are chimeric porin polypeptides comprising a first polypeptide comprising an amino-terminal domain of Mycobacterium tuberculosis porin and a second polypeptide comprising an antigen and the use the chimeric porin polypeptides in methods of eliciting an immune response in a subject.

Abstract: The present invention relates to improved electrochemical biosensor strips and methods for determining the concentration of an analyte in a sample. By selectively measuring a measurable species residing in a diffusion barrier layer, to the substantial exclusion of the measurable species residing exterior to the diffusion barrier layer, measurement errors introduced by sample constituents, such as red blood cells, and manufacturing variances may be reduced.

Abstract: An electrochemical test strip is provided, including a substrate, an electrode structure and an insulative film. The electrode structure is formed on the substrate, including a first electrode and a second electrode. The second electrode includes a first end, a second end, an extension portion, and a bent portion. The extension portion connects the first end with the bent portion, and the bent portion is connected to the second end. The extension portion and the first electrode define a space therebetween for receiving the bent portion. The insulative film covers at least a part of the electrode structure and forms an opening. A sample fluid enters the electrochemical test strip through the opening, and the sample fluid sequentially contacts the first electrode and the second electrode.

Abstract: A thin film sensor, such as a glucose sensor, is provided for transcutaneous placement at a selected site within the body of a patient. The sensor includes several sensor layers that include conductive layers and includes a proximal segment defining conductive contacts adapted for electrical connection to a suitable monitor, and a distal segment with sensor electrodes for transcutaneous placement. The sensor electrode layers are disposed generally above each other, for example with the reference electrode above the working electrode and the working electrode above the counter electrode. The electrode layers are separated by dielectric layer.

Abstract: A thin film sensor, such as a glucose sensor, is provided for transcutaneous placement at a selected site within the body of a patient. The sensor includes several sensor layers that include conductive layers and includes a proximal segment defining conductive contacts adapted for electrical connection to a suitable monitor, and a distal segment with sensor electrodes for transcutaneous placement. The sensor electrode layers are disposed generally above each other, for example with the reference electrode above the working electrode and the working electrode above the counter electrode. The electrode layers are separated by dielectric layer.

Abstract: A calibration method, including steps of: providing a test meter having a socket provided with a set of conductive pins; providing a biosensor test strip having a set of strip electrodes corresponding to the set of conductive pins, wherein the combination of lengths of the strip electrodes corresponds to a parameter code; inserting the biosensor test strip into the socket of the test meter so that each of the conductive pins and each of the corresponding strip electrode have a relative motion; reading out the parameter code by using a set of pulse widths detected by each of the conductive pins in the insertion period; and calibrating the test meter by using the parameter code to match a calibration parameter installed in the test meter.

Abstract: Various embodiments that allow for a more accurate analyte concentration by determining at least one physical characteristic, particularly hematocrit, of the blood sample containing the analyte, particularly glucose, and deriving a specific sampling time based on a relationship between the physical characteristic and sampling time so that the analyte concentration can be determined with greater accuracy with the specific sampling time point.

Abstract: A method for monitoring the metabolic state of an organelle in the presence of a potential organelle modulating agent is disclosed. A first organelle-modified bioelectrode is provided that is electrically coupled to a second electrode of opposite polarity in a circuit. The first bioelectrode is contacted with an aqueous carrier containing a biologically acceptable electrolyte and an effective amount of a potential organelle modulating agent and an effective amount of an organelle substrate. The substrate is reacted at the bioelectrode to form an ionic product that is released into the aqueous carrier-containing electrolyte to thereby provide a current at the second electrode when the circuit is closed. A metabolic flux data set is obtained during the reaction and is compared to a control metabolic flux data set obtained under the same conditions in the absence of the organelle modulating agent, thereby determining the metabolic state of the organelle.

Abstract: A flavin-binding glucose dehydrogenase (FAD-GDH), which in addition to having high substrate specificity and adequate desirable heat stability, is suitable for efficient production, preferably using E. coli, yeast or molds and the like as host cells. The FAD-GDH has amino acid substitutions at positions equivalent to one or more locations selected from the group consisting of position 213, position 368 and position 526 in the amino acid sequence described in SEQ ID NO: 8. The FAD-GDH is acquired from a culture by inserting a gene encoding the FAD-GDH into host cells such as E. coli. A preferable example of the FAD-GDH is FAD-GDH, in which a signal peptide region present in an N-terminal region has been deleted from the amino acid sequence of Mucor-derived FAD-GDH, and which has the aforementioned amino acid substitutions. The FAD-GDH can be preferably used in clinical diagnosis.

Abstract: The present invention provides a method to analyze or identify a cell. The method comprises: providing a cell, stimulating the cell with a stimulant thereby modifying a cell membrane impedance of the cell, monitoring the cell membrane impedance of the cell and identifying the cell based on the monitored cell membrane impedance. A corresponding device is also provided.

Abstract: A method for estimation of hematocrit of a sample having an analyte includes: bringing the sample into contact with a sensor strip including a reference electrode coated with a reference layer nonreactive to the analyte, and a working electrode coated with a working layer including a biorecognition element reactive to the analyte; applying a voltage between the reference and working electrodes, and recording information of a reaction current flowing through the sample within a time period of not greater than 5 seconds from beginning of application of the voltage; and estimating the hematocrit of the sample by analyzing the recorded information using a predetermined current-hematocrit function.

Abstract: A preparation method for molecular recognition sensor by electrodeposition is provided. The preparation method is as following: forming molecularly imprinted polymeric micelles by self-assembly of ionic type photosensitive copolymers; forming a film on the surface of an electrode by electrodepositing the molecularly imprinted polymeric micelles at a constant potential; crosslinking the electrodeposited micellar film via ultraviolet light irradiation; extracting the template molecules from the crosslinked film to obtain electrode modified by the molecularly imprinted polymeric micellar film; and connecting the modified electrode with a sensor device and a computer to construct a molecular recognition sensing system capable of specifically detecting the template molecules.

Abstract: A sterilization indicator system and method of using the system to determine efficacy of a sterilization process. The system may include a vial having an optional first compartment and a second compartment comprising a growth medium comprising one or more of a disaccharide, an oligosaccharide or a polysaccharide capable of conversion to a monosaccharide by germinating spores of the one or more species of microorganism, the vial being free of the monosaccharide prior to use; a strip including two or more electrodes to oxidize the monosaccharide and to carry a resulting electrical signal, and an apparatus to detect and measure the electrical signal resulting from the oxidation. Spores of a suitable biological indicator may be disposed in the first compartment and/or on the strip.

Abstract: A method for obtaining information encoded on an electrochemical test strip is provided. The test strip has two electrodes disposed within a sample space and the information is encoded on the test strip prior to introduction of liquid sample. The method includes the step of introducing sample to the sample space so that the sample is in contact with the two electrodes within the sample space. In another step a value is determined that is representative of the double layer capacitance of the test strip and/or the equivalent capacitance of the test strip. The determined value is then translated into information reflecting a characteristic of the test strip prior to introduction of sample.

Abstract: A method for determining glucose concentration in tear fluid includes providing a blood glucose test strip having glucose dehydrogenase as an active enzyme provided therein, receiving a tear fluid sample via fluid communication of the blood glucose test strip with an eye region of a subject, and processing the tear fluid sample to determine a tear glucose concentration. The method may further include correlating the determined tear glucose concentration with a blood glucose concentration.

Abstract: A method to detect beta-lactoglobulin (BLG) is described. The method includes the steps of adding a known concentration of hydrogen peroxide to a sample known to, or suspected of containing BLG; and electrolyzing the sample using a working electrode at a fixed potential sufficient to electrolyze BLG, and measuring a current signal within the sample. A diminution of the current signal in the sample as compared to a corresponding current signal from a standard solution containing a known concentration of hydrogen peroxide and no BLG indicates that the sample contains BLG.

Abstract: 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.

Abstract: A biosensor for quantifying an analyte in a sample and usage thereof are provided. The biosensor includes an insulative substrate, a cover, a sample supply port, an electrode system including at least a working electrode, a counter electrode and a third electrode, and a reaction layer at least formed over the working electrode. The third electrode, used for estimating whether the amount of the sample is sufficient, is disposed nearer to the sample supply port than the counter electrode is. Whether the amount of the added sample is sufficient is estimated by comparing the electrical current value detected between the working electrode and the counter electrode with the electrical current value detected between the working electrode and the third electrode. This invention has a simple structure and produces accurate measurements.

Abstract: Apparatus and methods are described for preparing, maintaining, and stabilizing sensors. The apparatus and methods for preparing sensors for use are utilized in advance of the sensor being removed from a sealed, sterilized package. The apparatus include packaging materials having electrical circuits capable of stabilizing a sensor to prepare the sensor for use. The methods for preparing a sensor for use includes methods of providing a solution to a sterilized packaging that contains a sensor connected to a sensor activating circuit, activating the circuit, and allowing the sensor to stabilize. These methods can be performed without compromising the packaging. The apparatus for stabilizing a sensor that is in use include a circuit connectable to the sensor that provides a signal to the sensor that prevents the sensor from becoming destabilized when disconnected from a monitoring device.

Abstract: Biosensors and biosensor systems are disclosed that have manganese (III) oxide (Mn2O3)-based electrodes that can attenuate interference of a detection signal resulting from an analyte-relevant reaction caused by undesired reaction of interferents in a sample. Methods are also disclosed for making and using the same.

Abstract: Compositions, devices, kits and methods are disclosed for assaying cholesterol with a cholesterol oxidase mutant that has been modified at an amino acid residue involved in the active site. The cholesterol oxidase mutant has reduced oxidase activity while substantially maintaining its dehydrogenase activity.

Abstract: A sensor utilizing a non-leachable or diffusible redox mediator is described. The sensor includes a sample chamber to hold a sample in electrolytic contact with a working electrode, and in at least some instances, the sensor also contains a non-leachable or a diffusible second electron transfer agent. The sensor and/or the methods used produce a sensor signal in response to the analyte that can be distinguished from a background signal caused by the mediator. The invention can be used to determine the concentration of a biomolecule, such as glucose or lactate, in a biological fluid, such as blood or serum, using techniques such as coulometry, amperometry, and potentiometry. An enzyme capable of catalyzing the electrooxidation or electroreduction of the biomolecule is typically provided as a second electron transfer agent.

Abstract: A sensor utilizing a non-leachable or diffusible redox mediator is described. The sensor includes a sample chamber to hold a sample in electrolytic contact with a working electrode, and in at least some instances, the sensor also contains a non-leachable or a diffusible second electron transfer agent. The sensor and/or the methods used produce a sensor signal in response to the analyte that can be distinguished from a background signal caused by the mediator. The invention can be used to determine the concentration of a biomolecule, such as glucose or lactate, in a biological fluid, such as blood or serum, using techniques such as coulometry, amperometry, and potentiometry. An enzyme capable of catalyzing the electrooxidation or electroreduction of the biomolecule is typically provided as a second electron transfer agent.

Abstract: A sensor utilizing a non-leachable or diffusible redox mediator is described. The sensor includes a sample chamber to hold a sample in electrolytic contact with a working electrode, and in at least some instances, the sensor also contains a non-leachable or a diffusible second electron transfer agent. The sensor and/or the methods used produce a sensor signal in response to the analyte that can be distinguished from a background signal caused by the mediator. The invention can be used to determine the concentration of a biomolecule, such as glucose or lactate, in a biological fluid, such as blood or serum, using techniques such as coulometry, amperometry, and potentiometry. An enzyme capable of catalyzing the electrooxidation or electroreduction of the biomolecule is typically provided as a second electron transfer agent.

Abstract: A sensor utilizing a non-leachable or diffusible redox mediator is described. The sensor includes a sample chamber to hold a sample in electrolytic contact with a working electrode, and in at least some instances, the sensor also contains a non-leachable or a diffusible second electron transfer agent. The sensor and/or the methods used produce a sensor signal in response to the analyte that can be distinguished from a background signal caused by the mediator. The invention can be used to determine the concentration of a biomolecule, such as glucose or lactate, in a biological fluid, such as blood or serum, using techniques such as coulometry, amperometry, and potentiometry. An enzyme capable of catalyzing the electrooxidation or electroreduction of the biomolecule is typically provided as a second electron transfer agent.

Abstract: A technique and a sensor chip allowing determination of a hematocrit value of a blood sample in a short period of time with low cost are provided. A response current obtained by sweep of a voltage applied across a working electrode for determination and a counter electrode for determination included in a sensor chip is measured and a hematocrit value is derived based on followability of the response current to temporal change in swept applied voltage. Therefore, it is not necessary to stand by until oxidation reduction reaction of an oxidation reducing substance is stabilized for determining a hematocrit value as in a conventional method of determining a hematocrit value, and thus a hematocrit value of a blood sample can be determined in a short period of time. Since no oxidation reducing substance is necessary for determining a hematocrit value, a hematocrit value can be determined with low cost.

Abstract: Compositions, devices, kits and methods are disclosed for assaying glucose with a glucose oxidase mutant that has been modified at an amino acid residue involved in the active site. The glucose oxidase mutant has reduced oxidase activity while substantially maintaining its dehydrogenase activity.

Abstract: A method and system is provided to allow for determination of substantially Hematocrit independent analyte concentration. In one example, an analyte measurement system is provided that includes a test strip and a test meter. The test strip includes a reference electrode and a working electrode, in which the working electrode is coated with a reagent layer. The test meter includes an electronic circuit and a signal processor. The electronic circuit applies a plurality of voltages to the reference electrode and the working electrode over respective durations. The signal processor is configured to determine a substantially hematocrit-independent concentration of the analyte from a plurality of current values as measured by the processor upon application of a plurality of test voltages to the reference and working electrodes over a plurality of durations interspersed with rest voltages lower than the test voltages being applied to the electrodes.

Abstract: An electrochemical test sensor for detecting the analyte concentration of a fluid test sample includes a base, a dielectric layer, a reagent layer, a light guide area, and a lid. The base provides a flow path for the test sample having on its surface a counter electrode and a working electrode adapted to electrically communicate with a detector of electrical current. The dielectric layer forms a dielectric window therethrough. The reagent layer includes an enzyme that is adapted to react with the analyte. The lid is adapted to mate with the base and to assist in forming a capillary space with an opening for the introduction of the test sample thereto. The light guide area transmits light towards the capillary space.

Abstract: Embodiments of the invention provide amperometric analyte sensors having optimized elements such as electrodes formed from sputtered platinum compositions as well as layers of material selected to optimize the characteristics of a wide variety of sensor elements and sensors. While embodiments of the innovation can be used in a variety of contexts, typical embodiments of the invention include glucose sensors used in the management of diabetes.

Abstract: A sensor designed to determine the concentration of analyte in a sample having a volume of less than about 1 ?L. The sensor has a working electrode coated with a redox mediator that acts as an electron transfer agent between the analyte and the electrode. A second electron transfer agent, such as an enzyme, can be added to facilitate the electrooxidation or electroreduction of the analyte. Various electrochemical detection methods, such as amperometric, voltammetric, and potentiometric techniques, can be used to determine the analyte concentration. The sensor can be used to determine the concentration of a biomolecule, such as glucose or lactate, in a biological fluid, such as blood or serum.

Abstract: A test strip, a detecting device, and a detecting method are disclosed. The test strip includes a first specimen path, a first electrode set, a second specimen path, a second electrode set, and a reaction reagent. When the specimen contacts the first electrode set and the second electrode set, a first pulse signal and a second pulse signal are generated for obtaining a flow time of the specimen. When the specimen contacts the reaction reagent, the analyte concentration of the specimen can be obtained, and the concentration of the analyte can be corrected by the flow time.

Abstract: A biosensor is a bio sensor for measuring concentrations of first and second substrates in a sample, including a sensor unit including an insulating base plate, an electrode over the insulating base plate, and a reaction layer over the electrode; a timing unit for measuring time; and a calculating unit, in which the reaction layer contains a first enzyme for converting the first substrate into the second substrate, and a second enzyme acting on the second substrate or the converted substance obtainable by further converting the second substrate, and the calculating unit calculates concentrations of the first and the second substrates in the sample, on the basis of a first current value detected in the sensor unit at a first time and a second current value detected in the sensor unit at a second time.

Abstract: The invention relates to a method of determining a charged particle concentration in an analyte (100), the method comprising steps of: i) determining at least two measurement points of a surface-potential versus interface-temperature curve (c1, c2, c3, c4), wherein the interface temperature is obtained from a temperature difference between a first interface between a first ion-sensitive dielectric (Fsd) and the analyte (100) and a second interface between a second ion-sensitive dielectric (Ssd) and the analyte (100), and wherein the surface-potential is obtained from a potential difference between a first electrode (Fe) and a second electrode (Se) onto which said first ion-sensitive dielectric (Fsd) and said second ion-sensitive dielectric (Ssd) are respectively provided, And ii) calculating the charged particle concentration from locations of the at least two measurement points of said curve (c1, c2, c3, c4).

Abstract: Various embodiments that allow for determination of hematocrit by a time differential between the input and output signals such that a glucose measurement for a blood sample can be corrected by the measured hematocrit of the blood sample.

Abstract: The claimed subject matter relates to the stabilization of 1,2-quinone mediators, especially those containing 1,10-phenanthroline quinone (PQ) and more especially transition metal complexes of PQ, in the presence of enzymes when contained in dry reagent layers for biosensor electrodes, through the use of various metal salts, particularly those of lithium.

Abstract: An eye-mountable device includes an electrochemical sensor embedded in a polymeric material configured for mounting to a surface of an eye. The electrochemical sensor applies a stabilization voltage between a working electrode and a reference electrode to allow the amperometric current to stabilize before powering measurement electronics configured to measure the amperometric current and communicate the measured amperometric current. The electrochemical sensor consumes less power while applying the stabilization voltage than during the measurement. The measurement is initiated in response to receiving a measurement signal at an antenna in the eye-mountable device.

Abstract: The method includes: acquiring data a related to a temperature of a blood sample on a sensor chip, based on a dimension of a current flowing in the blood sample by applying a first voltage to the pair of electrodes in contact with the blood sample, the first voltage being set so as to reduce an effect of hematocrit on a temperature measurement result; acquiring data b related to the concentration of an analyte in the blood sample, based on a dimension of a current flowing in the blood sample by applying a second voltage that is equal to or less than the first voltage, utilizing a reaction mediated by an oxidoreductase that uses the analyte in the blood sample as a substrate; and measuring a concentration that determines the analyte concentration in the blood sample based on the data a and the data b.

Abstract: According to one embodiment of the present invention, an electrochemical sensor (10) for detecting the concentration of analyte in a fluid test sample is disclosed. The sensor (10) includes a counter electrode having a high-resistance portion for use in detecting whether a predetermined amount of sample has been received by the test sensor.

Abstract: A glucose sensor suitable for measuring glucose levels in human saliva is provided. Systems containing the glucose sensor and methods for making and using the sensor are also provided. The glucose sensor is highly sensitive and can detect glucose levels at least down to 5 ppm. Fabrication of the sensor involves depositing single-walled carbon nanotubes onto the surface of a working electrode in a 3 electrode electrochemical detector and functionalizing the nanotubes by depositing layers of polymers, metallic nanoparticles, and glucose oxidase enzyme onto the nanotubes. The sensor can be used as a disposable, single-use device or as part of an analytical system, such as a microfluidics system, for the analysis of multiple analytes. The sensor enables the diagnosis and monitoring of diabetes to be performed without pain or the need for finger pricks in a home or clinical setting.

Abstract: An amperometric biosensor is adapted for detecting concentration of a target analyte, and includes a detector and a plurality of sensing members connected electrically to form an input of the detector. Each sensing member includes an electrode unit including a working electrode with a biorecognition element disposed thereon for reaction with the target analyte, and a reference electrode. Each sensing member receives the target analyte, so as to bring the target analyte into contact with the working and reference electrodes. The detector provides a voltage to each electrode unit, so as to generate a current that flows through the target analyte and that is detected for subsequent concentration analysis of the target analyte.

Abstract: Methods for distinguishing between an aqueous non-blood sample (e.g., a control solution) and a blood sample are provided herein. In one aspect, the method includes using a test strip in which multiple current transients are measured by a meter electrically connected to an electrochemical test strip. The current transients are used to determine if a sample is a blood sample or an aqueous non-blood sample based on at least two characteristics (e.g., amount of interferent present and reaction kinetics). The method can also include calculating a discrimination criteria based upon at least two characteristics. Various aspects of a system for distinguishing between a blood sample and an aqueous non-blood sample are also provided herein.

Abstract: Provided is a method for processing a sample, which method comprises: a) contacting a binding phase, which binding phase is capable of binding an analyte, with the sample in the presence of a medium; b) applying across the medium a first alternating field composed of a plurality of pulses and having a first frequency, a first pulse duration and a first pulse rise time; c) optionally applying across the medium a second alternating field; and d) thereby influencing the sample and/or the binding phase in the medium.

Abstract: Disclosed herein is a device that functions as a glucose sensor. The device has a reference electrode; a counter electrode, a working electrode; an electrically conducting membrane; an enzyme layer; a semi-permeable membrane; a first layer of a first hydrogel in operative communication with the working electrode; the first layer of the first hydrogel being operative to store oxygen; wherein the amount of stored oxygen is proportional to the number of freeze-thaw cycles that the hydrogel is subjected to; and a second layer of the second hydrogel. Disclosed too is a method that comprises using periodically biased amperometry towards interrogation of implantable glucose sensors to improve both sensor's sensitivity and linearity while at the same time enable internal calibration against sensor drifts that originate from changes in either electrode activity or membrane permeability as a result of fouling, calcification and/or fibrosis.

Abstract: A method of a test strip detecting concentration of an analyte of a sample includes placing the sample in a reaction region of the test strip, wherein the analyte reacts with an enzyme to generate a plurality of electrons, and the plurality of electrons are transferred to a working electrode of the reaction region through a mediator; applying an electrical signal to the working electrode; measuring a first current through the working electrode during a first period; the mediator generating an intermediate according to the electrical signal during a second period; measuring a second current through the working electrode during a third period; calculating initial concentration of the analyte according to the first current; calculating a diffusion factor of the intermediate in the sample according to the second current; and correcting the initial concentration to generate new concentration of the analyte according to the diffusion factor.

Abstract: An analytical test strip has mutually-insulated first and second electrodes arranged to define a sample-receiving chamber. Electrically-insulating layers are disposed over respective electrodes. First and second electrical contact pads are electrically connected to the first electrode, and a third pad to the second electrode. A first side of the test strip has a first electrically-insulating layer and the third pad, and a second side has the second electrically-insulating layer and the first and second pads. The third pad extends longitudinally from the sample-receiving chamber farther than does the first electrically-insulating layer. Methods for determining an analyte in a bodily-fluid sample and analytical test systems for use in the determination of an analyte in a bodily-fluid sample are also described.

Abstract: A method for detecting the presence of an analyte in a sample. The method comprises the steps of: adding to the sample an antibody of the analyte; exposing to the sample a binding moiety capable of becoming associated with the antibody of the analyte, the binding moiety being associated with a redox active species that is bound to an electrode and electrochemically accessible to the electrode; and taking amperometric electrochemical measurements which indicate whether the electrochemistry of the redox active species has been modulated by the binding moiety associating with the antibody of the analyte.

Abstract: An electrochemical sensor comprising an electrode having a protective layer; conductive nanoparticles bound to the protective layer; a redox active species bound to the conductive nanoparticles; and a binding moiety capable of associating with an analyte, the binding moiety being associated with the redox active species bound to the conductive nanoparticles. Association of a binding moiety with the analyte modulates the electrochemistry of the redox active species.