Electrochemical Sensor Diffusion Correction via Current Transient Analysis
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Solution Overview
Problem
Existing electrochemical sensors for fluidic samples, such as blood glucose monitors, face accuracy issues due to diffusion interfering factors (DIF) like blood haematocrit and redox interfering factors (RIF) like uric acid, which current technologies struggle to mitigate simultaneously, leading to inaccuracies in analyte measurements.
Innovation Solution
A method and device that utilize redox reactions in an electrochemical cell with at least two electrodes to simultaneously determine diffusion features and the contribution of redox-active substances, using measured current and time parameters to correct for both DIF and RIF, allowing for accurate analyte measurement by identifying a turning point in the current transient and applying calibration information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If active DIF mitigation is used to correct diffusion interfering factors, then diffusion measurement accuracy is improved, but strip-to-strip variations in sample chamber height cause measurement inconsistency
Solution Approach 1:
The patent uses feedback by measuring the actual current transient response of each individual strip and using that information to dynamically determine the measurement time. The system monitors the current over time and identifies when the Cottrell decay pattern is established, then uses this feedback to adjust the measurement timing for that specific strip, compensating for manufacturing variations in sample chamber height.
Solution Approach 2:
The patent implements dynamics by transitioning from a fixed measurement time approach to a dynamic measurement time determination. The system continuously monitors the current transient response and adapts the measurement timing based on the actual electrochemical behavior observed for each strip, allowing the measurement parameters to change in real-time based on strip-specific characteristics.
2Measurement precision
If active RIF mitigation is used to correct redox interfering factors, then redox interference accuracy is improved, but simultaneous mitigation of both DIF and RIF increases device complexity
Solution Approach 1:
The patent merges DIF and RIF mitigation into a single integrated system. By using the current transient response to simultaneously determine both diffusion characteristics (through Cottrell decay analysis) and redox interference contributions (through deviation from ideal Cottrell behavior), the system achieves dual mitigation without requiring separate measurement systems or additional hardware components.
Solution Approach 2:
The patent implements universality by designing a single measurement system that performs multiple functions: it determines diffusion coefficients, identifies redox interfering substances, and corrects for both types of interference using the same electrochemical cell and data processing framework. The current transient response serves as a universal signal source for multiple analytical purposes.
3Ease of operation
If fixed measurement time is used, then device operation is simplified, but measurement accuracy varies across different strips due to chamber height variations
Solution Approach 1:
The patent applies preliminary action by performing a preliminary monitoring phase where the current transient response is measured over time before the final analyte quantification. This preliminary data collection allows the system to characterize the electrochemical behavior of each strip, identify the optimal measurement time, and establish the Cottrell decay pattern, which then informs the timing for the actual analyte measurement.
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 approach enables simultaneous measurement and correction for both diffusion and redox interfering factors, improving the accuracy of analyte measurements by quantifying diffusion properties like haematocrit and redox-active substances like uric acid, thereby enhancing the reliability of self-monitoring blood glucose tests and reducing errors from strip-to-strip variations.
Implementation Method 1
determining a diffusion feature of a fluidic sample using redox reactions in an electrochemical cell that has at least two electrodes
Implementation Method 2
determining diffusion between the two electrodes across the strip sample chambers
Data Source
Figure 1~2
Figure 3a
Figure 3b
AI summary
A method for determining a diffusion feature of a fluidic sample using redox reactions in an electrochemical cell that has at least two electrodes, wherein the first electrode has at least one redox mediator at its surface or in close vicinity of its surface, and the second electrode has an electrode surface free of the redox mediator(s) in the beginning of a test, the method comprising: applying an electric potential to a fluidic sample in the electrochemical cell to initiate redox reactions at the two electrode surfaces; measuring current associated with the applied potential as a function of time, and using a measurement point on a transient part of the measured current at or after a turning point and its associated time to determine the diffusion feature.