Glucose Sensor Electrochemical Interference Detection

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Solution Overview

Problem

Continuous glucose monitoring (CGM) systems face electrochemical interference due to insulin excipients and other substances, leading to inaccurate glucose readings, which can result in improper insulin dosages and adverse effects for diabetic patients.

Innovation Solution

The implementation of electrochemical impedance spectroscopy (EIS) to monitor and detect electrochemical interference by measuring electrical impedances at various frequencies, determining charge transfer conductance and solution resistance, and outputting signals to indicate interference, thereby correcting sensor readings.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If electrochemical impedance spectroscopy (EIS) is implemented to detect electrochemical interference, then measurement precision is improved, but device complexity increases

Engineering Contradiction:
Improveglucose reading accuracyVSAvoidsensor system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the impedance measurement process into multiple frequency points (at least two different frequencies) to detect electrochemical interference. By measuring impedance at different frequencies and comparing the results, the system can identify interference conditions without requiring a single complex measurement technique, thus improving precision while managing device complexity through procedural segmentation.

Inventive Principle:
Principle #1Segmentation

2Reliability

If impedance measurements are taken at multiple frequencies to detect interference, then reliability is improved, but loss of time increases

Engineering Contradiction:
Improveglucose measurement reliabilityVSAvoidmeasurement time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent applies preliminary action by performing impedance measurements at multiple frequencies before final glucose calculation. The system measures impedance at different frequencies, compares these preliminary measurements to detect interference, and only then proceeds with accurate glucose determination. This preliminary detection step ensures reliability by identifying interference conditions early, preventing wasted time on inaccurate measurements.

Inventive Principle:
Principle #10Preliminary action

3Measurement precision

If electrochemical interference is detected and corrected, then measurement precision is improved, but device complexity increases

Engineering Contradiction:
Improveglucose reading accuracyVSAvoidprocessing complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent implements feedback by using impedance measurement results to inform and adjust the glucose measurement process. The system measures impedance at multiple frequencies, uses these results to detect electrochemical interference, and then applies appropriate corrections or flags to the glucose reading based on the interference detection. This feedback loop improves precision by accounting for interference conditions while managing complexity through systematic processing rules.

Inventive Principle:
Principle #23Feedback

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

This method effectively identifies and mitigates electrochemical interference, ensuring accurate glucose monitoring and reducing the risk of adverse effects by providing reliable glucose readings for diabetic patients.

Implementation Method 1

measuring, via the device, a plurality of impedances of the electrochemical cell corresponding to a plurality of frequencies; determining a charge transfer conductance and a solution resistance based on the plurality of impedances

Methodology Applied
Scientific EffectElectrochemical impedance spectroscopy: Electrical Resistance

Data Source

PatentEP4183331A1Glucose sensor
Publication Date: 2023.05.24 MEDTRONIC MINIMED INC
  • EP4183331A1 patent drawingFigure 1
  • EP4183331A1 patent drawingFigure 2
  • EP4183331A1 patent drawingFigure 3A

AI summary

A method includes monitoring, via a device including an electrochemical cell, an electrical current that is proportional to an impedance of the electrochemical cell, and responsive to determining that the electrical current satisfies a threshold, measuring, via the device, a plurality of impedances of the electrochemical cell corresponding to a plurality of frequencies. The method further includes determining a charge transfer conductance and a solution resistance based on the plurality of impedances at fewer than four of the corresponding plurality of frequencies and determining the presence of electrochemical interference based on the solution resistance and the charge transfer conductance. The method further includes outputting an alert based on the determination of the presence of electrochemical interference.