EIS Glucose Sensor Diagnostics for Fast Stabilization and Calibration
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Solution Overview
Problem
Current continuous glucose monitoring systems face issues such as sensor stabilization time, inaccurate readings due to insufficient electrode hydration, unreliable operation beyond the specified life, lack of real-time diagnostics, and reliance on finger sticks for calibration, and limited use of redundant electrodes for improved accuracy.
Innovation Solution
Implementing electrochemical impedance spectroscopy (EIS) for real-time sensor diagnostics, including methods for sensor stabilization, electrode characterization, contaminant detection, and calibration, using a system with redundant electrodes and advanced electronics for sensor health assessment and interferent detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If a patient uses a continuous glucose sensor immediately after insertion, then the sensor provides early glucose measurements, but the readings are inaccurate due to insufficient electrode hydration and stabilization
Solution Approach 1:
The system performs preliminary electrode hydration and stabilization actions before glucose measurements are taken. The sensor applies voltage pulses and conducts self-tests during an initialization period to prepare the electrodes for accurate measurements, ensuring the electrodes are properly hydrated and the sensor is stabilized before clinical use.
Solution Approach 2:
The system uses feedback mechanisms to monitor sensor performance and determine when stabilization is complete. Self-test measurements and quality control checks provide feedback about electrode condition and signal quality, allowing the system to automatically determine when the sensor is ready for accurate glucose monitoring without requiring fixed waiting periods.
2Duration of action of stationary object
If a sensor operates beyond its specified life, then the sensor continues to function, but the readings become unreliable and diagnostic capability is lost
Solution Approach 1:
The system continuously monitors sensor performance through self-tests and quality control measurements, providing feedback about sensor health and detection capability. This feedback mechanism allows the system to track sensor degradation over time and determine when the sensor has lost sufficient diagnostic capability to warrant replacement, even if the sensor continues to produce readings.
Solution Approach 2:
The sensor performs self-diagnostic tests and self-assessment of its own detection capability throughout its operational life. The sensor automatically evaluates its own electrode condition, signal quality, and functional performance without external intervention, enabling it to self-determine when it has reached the end of its reliable operational period.
3Reliability
If a sensor system includes redundant electrodes and advanced diagnostics, then the system provides improved accuracy and real-time monitoring, but the device complexity increases
Solution Approach 1:
The system combines multiple functions into integrated sensor components. Redundant electrodes serve both as backup sensing elements and as diagnostic tools for assessing sensor health. The same electrode structures are used for both glucose detection and for performing self-tests, eliminating the need for separate diagnostic components and reducing overall system complexity.
Solution Approach 2:
The sensor electrodes are designed to perform multiple functions: primary glucose detection, redundant backup sensing, self-diagnostic testing, and quality control measurements. This multi-functionality allows the system to achieve high reliability and real-time monitoring capabilities without adding separate dedicated components for each function, thereby limiting the increase in device complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables rapid sensor stabilization, accurate readings, extended sensor life, reduces the need for finger sticks, and provides reliable real-time monitoring and calibration, enhancing the overall performance and reliability of continuous glucose monitoring systems.
Implementation Method 1
performing a first electrochemical impedance spectroscopy (EIS) procedure to generate a first set of impedance-related data for the at least one working electrode
Implementation Method 2
a sensor in contact with a bodily fluid, an optical sensor, an enzymatic sensor, or a fluorescent sensor
Data Source
AI summary
A diagnostic Electrochemical Impedance Spectroscopy (EIS) procedure is applied to measure values of impedance-related parameters for one or more sensing electrodes. The parameters may include real impedance, imaginary impedance, impedance magnitude, and/or phase angle. The measured values of the impedance-related parameters are then used in performing sensor diagnostics, calculating a highly-reliable fused sensor glucose value based on signals from a plurality of redundant sensing electrodes, calibrating sensors, detecting interferents within close proximity of one or more sensing electrodes, and testing surface area characteristics of electroplated electrodes. Advantageously, impedance-related parameters can be defined that are substantially glucose-independent over specific ranges of frequencies. An Application Specific Integrated Circuit (ASIC) enables implementation of the EIS-based diagnostics, fusion algorithms, and other processes based on measurement of EIS-based parameters.