Analyte sensors and methods for improving interferent rejection and longevity
AssigneeMedtronic MiniMed, Inc.
InventorsRobert M. McKinlay, Quyen B. Ong, Xin Heng, Weihong Cui
Life of this patent
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Abstract
An analyte sensor includes a microcontroller, a base layer, a conductive layer disposed on the base layer where the conductive layer includes a working electrode configured to provide a current signal in presence of glucose, an interference rejection membrane (“IRM”) layer disposed on the working electrode where the IRM layer is negatively charged, and an enzyme layer disposed on the IRM layer where the enzyme layer includes an enzyme selected to generate a detectable electrical signal upon exposure to the glucose. The microcontroller is configured to process an electrochemical impedance spectroscopy (EIS) parameter to determine a state of the IRM layer.
Claims14
An analyte sensor comprising:
- a microcontroller;
- a base layer;
- a conductive layer disposed on the base layer, wherein the conductive layer includes a working electrode configured to provide a current signal in presence of glucose;
- an interference rejection membrane (“IRM”) layer disposed on the working electrode, the IRM layer being negatively charged;
- and
- an enzyme layer disposed on the IRM layer, wherein the enzyme layer includes an enzyme selected to generate a detectable electrical signal upon exposure to the glucose,
- wherein the microcontroller is configured to process an electrochemical impedance spectroscopy (EIS) parameter to determine a state of the IRM layer, and
- wherein the microcontroller is further configured to determine an EIS signature value based on a dielectric property of the IRM layer.
A method in an analyte sensor,
- the analyte sensor comprising:
- a microcontroller;
- a base layer for supporting the analyte sensor;
- a conductive layer disposed on the base layer, wherein the conductive layer includes a working electrode configured to provide a current signal in presence of glucose;
- an interference rejection membrane (“IRM”) layer disposed on the working electrode, the IRM layer being negatively charged;
- and
- an enzyme layer disposed on the IRM layer, wherein the enzyme layer includes an enzyme selected to generate a detectable electrical signal upon exposure to the glucose;
- the method comprising:
- by the microcontroller, processing an electrochemical impedance spectroscopy (EIS) parameter to determine a state of the IRM layer of the analyte sensor, wherein the EIS parameter is median imaginary impedance, and
- wherein processing the EIS parameter to determine the state of the IRM layer includes determining the state of the IRM layer based on the median imaginary impedance.
A method of identifying adjusting a sensor value when an early wear run-in problem occurs in an analyte sensor, the method comprising:
- implanting an analyte sensor into a body of a user, wherein the analyte sensor comprises:
- a base layer for supporting the analyte sensor;
- a conductive layer disposed on the base layer, wherein the conductive layer includes a working electrode configured to provide a current signal in presence of glucose;
- an interference rejection membrane (“IRM”) layer disposed on the working electrode, the IRM layer being negatively charged;
- and
- an enzyme layer disposed on the IRM layer, wherein the enzyme layer includes an enzyme selected to generate a detectable electrical signal upon exposure to the glucose;
- accessing an electrochemical impedance spectroscopy (EIS) signature value for each predetermined period during an initial portion of a lifetime of the analyte sensor;
- calculating a difference between the EIS signature value and a reference value;
- and
- adjusting a sensor value when the difference between EIS signature values and the reference value is greater than a predetermined threshold,
- wherein the reference value is predetermined based on a design configuration of the analyte sensor, and
- wherein the EIS signature value is calculated based on a dielectric property of the IRM layer.
Dependencies are inferred from the claim text.