In various embodiments a molecular circuit is disclosed. The circuit comprises a negative electrode, a positive electrode spaced apart from the negative electrode, and an enzyme molecule conductively attached to both the positive and negative electrodes to form a circuit having a conduction pathway through the enzyme. In various examples, the enzyme is a polymerase. The circuit may further comprise molecular arms used to wire the enzyme to the electrodes. In various embodiments, the circuit functions as a sensor, wherein electrical signals, such as changes to voltage, current, impedance, conductance, or resistance in the circuit, are measured as substrates interact with the enzyme.

Flexible analyte sensors are provided. Flexible analyte sensors may be flexible continuous analyte sensors that facilitate continuous monitoring of an analyte such as blood glucose. The flexible analyte sensor may have a relatively flexible conductive or non-conductive core, may be formed from a plurality of substantially planar layers, or may be configured to transform from a freestanding sensor ex vivo to a non-freestanding sensor in vivo.

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.

Disclosed is a urea biosensor that is stable at ambient temperature, and methods of making thereof.

Devices, systems, and compositions of matter involving enzyme-mediated bioelectrocatalysis are disclosed and described. An enzyme electrode can include an electrode, a bioelectric material coupled to the electrode, the bioelectric material further including a water-permeable polymer matrix, a planar linker covalently coupled to the water-permeable polymer matrix and noncovalently coupled to the electrode, and electrochemically active oxidoreductase enzyme molecules functionally embedded in the water-permeable polymer matrix.

The present invention relates generally to systems and methods for measuring an analyte in a host. More particularly, the present invention relates to systems and methods for transcutaneous measurement of glucose in a host.

An apparatus for measuring a concentration of an analyte in a bio-sample using an electrochemical bio-sensor, includes a connector with a sample cell in which an oxidation/reduction enzyme and an electron transfer mediator are fixed and a working electrode and an counter electrode are provided; a digital-to-analog converter circuit configured to apply a constant DC voltage to start the oxidation/reduction reaction of the analyte, proceed with an electron transfer reaction, and apply a Λ-step ladder-type perturbation potential for fluctuating a potential of the sample cell after applying the constant DC voltage; and a microcontroller configured to control the digital-to-analog converter circuit and directly obtain a concentration value of the analyte from a calibration equation using the Λ-step ladder-type perturbation potential. The apparatus can improve measurement accuracy by effectively minimizing a matrix interference effect of a background material in a bio-sample, particularly an inaccuracy caused by a change in hematocrit.

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 a biointerface layer which interfaces with a biological fluid containing the analyte to be measured. The biointerface layer can comprises a biointerface polymer, wherein the biointerface polymer comprises polyurethane and/or polyurea segments and one or more zwitterionic repeating units. The sensing membrane can also comprise 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 sensing membrane can also comprise a diffusion-resistance layer, which can comprise a base polymer having a lowest Tg of greater than −50 C.

An enzyme sensor including a pair of electrodes, an electron transfer layer held between the pair of electrodes, and an electron generating capsule in which a membrane containing at least a substrate of an enzyme to be detected encloses at least one or more kinds of enzymes other than the enzyme to be detected, the electron generating capsule being in contact with the electron transfer layer.

Disclosed are multi-enzyme biosensors that are stable at ambient temperature, and methods of making thereof.