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 are devices for determining an analyte concentration. The devices comprise a sensor configured to generate a signal associated with a concentration of an analyte and an electronics unit operatively connected to the sensor. The electronics unit may be engaged with a housing that may secure the device to a host's skin. In this regard, in one embodiment, the housing may be attached to an adhesive patch that is fastened to the skin of the host.

Disclosed are devices for determining an analyte concentration. The devices comprise a sensor configured to generate a signal associated with a concentration of an analyte and an electronics unit operatively connected to the sensor. The electronics unit may be engaged with a housing that may secure the device to a host's skin. In this regard, in one embodiment, the housing may be attached to an adhesive patch that is fastened to the skin of the host.

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 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.