Circuitry for measuring a characteristic of an electrochemical cell, the circuitry comprising: a comparator having a first comparator input, a second comparator input and a comparator output; a feedback path between the comparator output and the second comparator input configured to provide a feedback signal to the second comparator input; and a loop filter configured to apply filtering to the feedback path to generate the feedback signal, wherein the loop filter comprises the electrochemical cell.

A high-gain and low-noise negative feedback control (“feedback control”) system can detect charge transfer in quantum systems at room temperatures. The feedback control system can attenuate dissipative coupling between a quantum system and its thermodynamic environment. The feedback control system can be integrated with standard commercial voltage-impedance measurement system, for example, a potentiostat. In one aspect, the feedback control system includes a plurality of electrodes that are configured to electrically couple to a sample, and a feedback mechanism coupled to a first electrode of the plurality of electrodes. The feedback mechanism is configured to detect a potential associated with the sample via the first electrode. The feedback mechanism provides a feedback signal to the sample via a second electrode of the plurality of electrodes, the feedback signal is configured to provide excitation control of the sample at a third electrode of the plurality of electrode.

Disclosed are devices for determining an analyte concentration (e.g., glucose). The devices comprise a sensor configured to generate a signal associated with a concentration of an analyte and a sensing membrane located over the sensor. The sensing membrane comprises an enzyme layer, wherein the enzyme layer comprises an enzyme and a polymer comprising polyurethane and/or polyurea segments and one or more zwitterionic repeating units. The enzyme layer protects the enzyme and prevents it from leaching from the sensing membrane into a host or deactivating.

A method is provided for determining analyte concentrations, for example glucose concentrations, that utilizes a dynamic determination of the appropriate time for making a glucose measurement, for example when a current versus time curve substantially conforms to a Cottrell decay, or when the current is established in a plateau region. Dynamic determination of the time to take the measurement allows each strip to operate in the shortest appropriate time frame, thereby avoiding using an average measurement time that may be longer than necessary for some strips and too short for others.

A system for determining a level of hematocrit includes a test strip configured to receive a sample; a meter configured to receive the test strip; and further including circuitry and a microprocessor, the circuitry and microprocessor configured to apply electrical energy to the test strip and the sample and determine an electrical property of the sample, either the impedance phase angle or the impedance magnitude of the test strip and the sample and, based on the electrical property, calculate the level of hematocrit in the sample.

A method for determining an information on an equivalent series resistance is disclosed and comprises: generating at least one excitation voltage signal and applying the excitation voltage to at least two measurement electrodes; measuring a response signal; determining a signal flank from the response signal and determining an ohmic signal portion from one or both of shape and height of the signal flank; and determining the information on the equivalent series resistance from the ohmic signal portion.

The present invention relates to systems that utilize a combination of immunoassay and magnetic immunoassay techniques to detect an analyte within an extended range of specified concentrations. In particular, a device is provided for detecting an analyte in a biological sample. The device includes a first electrochemical sensor positioned on a substrate. The first electrochemical sensor includes an immobilized layer of antibody configured to bind to the analyte. The device further includes a second electrochemical sensor positioned adjacent to the first electrochemical sensor on the substrate, and a magnetic material that generates a magnetic field aligned with respect to the second electrochemical sensor. The magnetic field captures magnetic beads that have an immobilized layer of antibody configured to bind to the analyte, and concentrates the magnetic beads on or near a surface of the second electrochemical sensor.

Described systems and methods allow the detection and quantitation of a target analyte such as a toxin, drug, pesticide, etc. Some embodiments use a sensor comprising photo-sensitive cells, e.g., cells genetically modified to express an opsin. A light source such as an LED is used to optically stimulate the sensor cells, triggering changes in a measurable quantity such as the polarization of the cell membrane. Some embodiments use electrical impedance measurements to monitor the cell's recovery from the state induced by the optical stimulation. The recovery process is affected by the presence of certain bio-active compounds, which allows detection and quantitation of such compounds.

Embodiments herein include systems and methods for detecting, predicting and/or assessing acute kidney injury. In an embodiment, a monitoring system to detect acute kidney injury is included. The monitoring system can include a sensor circuit configured to collect renal data including at least one of systemic renal data, direct renal data, urinary tract data, and renal-relevant extracorporeal data. The monitoring system can also include a memory circuit to store collected renal data, an evaluation circuit to assess renal status, and a telemetry circuit. The evaluation circuit can determine whether acute kidney injury has occurred or is likely to occur by comparing the renal data to at least one of threshold values, personal historical values, patient population values and patterns indicative of acute kidney injury. The evaluation circuit can initiate a warning notification if acute kidney injury has occurred or is likely to occur. Other embodiments are also included herein.

A sensor system, device, and methods for determining the concentration of an analyte in a sample is described. Gated voltammetric pulse sequences including multiple duty cycles of sequential excitations and relaxations may provide a shorter analysis time and/or improve the accuracy and/or precision of the analysis. The disclosed pulse sequences may reduce analysis errors arising from the hematocrit effect, variance in cap-gap volumes, non-steady-state conditions, mediator background, a single set of calibration constants, under-fill, and changes in the active ionizing agent content of the sensor strip.