Dual Electrode Sensor Corrects Oxygen Interference in Glucose Testing
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Solution Overview
Problem
Glucose oxidase-based test sensors are sensitive to oxygen levels in blood samples, leading to inaccuracies in glucose measurements, and existing reagents like PQQ-GDH and NAD-GDH have stability and cost issues, necessitating a solution to correct for the oxygen effect for more accurate analyte measurements.
Innovation Solution
An electrochemical test sensor design featuring two working electrodes and a counter electrode, where one electrode includes glucose oxidase, a mediator, and peroxidase, and the other includes glucose oxidase and a mediator, allowing for the measurement of currents to correct for the oxygen effect, thereby improving glucose concentration determination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If glucose oxidase is used in a test sensor, then the reagent cost is reduced and stability is improved, but the measurement precision deteriorates due to sensitivity to oxygen levels
Solution Approach 1:
The test sensor is divided into two separate working electrodes: a first working electrode containing glucose oxidase for measuring total oxygen consumption, and a second working electrode containing glucose oxidase and peroxidase for measuring oxygen consumption independent of glucose reaction. This segmentation allows independent measurement and calculation of the oxygen effect, enabling correction of glucose measurements to achieve both stability and precision.
Solution Approach 2:
Peroxidase is introduced as an intermediary substance in the second working electrode that catalyzes the decomposition of hydrogen peroxide. This intermediary enables the second electrode to measure oxygen consumption without the interference of the glucose oxidase reaction, providing a reference measurement for correcting the oxygen effect on glucose measurements.
2Device complexity
If a single working electrode with glucose oxidase is used, then the device complexity is reduced, but the measurement precision deteriorates due to inability to correct oxygen effect
Solution Approach 1:
The single working electrode is segmented into two separate working electrodes with different reagent compositions. The first electrode measures total oxygen consumption, while the second electrode with peroxidase measures reference oxygen consumption. This segmentation enables correction of the oxygen effect and improves measurement precision despite increased device complexity.
Solution Approach 2:
The reagent composition parameter is changed between the two working electrodes: the first electrode contains glucose oxidase only, while the second electrode contains glucose oxidase plus peroxidase. This parameter change creates different measurement conditions that allow calculation and correction of the oxygen effect on glucose measurements.
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
The sensor effectively corrects for the oxygen effect, enhancing the accuracy of glucose measurements and potentially applicable for other analytes like cholesterol and lactate, by using the difference in current measurements from the two electrodes to calculate corrected analyte concentrations.
Implementation Method 1
The first working electrode includes glucose oxidase, a mediator and peroxidase. The second working electrode includes glucose oxidase and the mediator.
Implementation Method 2
Glucose oxidase is currently not an expensive reagent, especially compared to NAD-GDH. In addition, glucose oxidase is generally a stable reagent
Implementation Method 3
The first working electrode includes glucose oxidase, a mediator and peroxidase. The second working electrode includes glucose oxidase and the mediator.
Implementation Method 4
The first working electrode includes glucose oxidase, a mediator and peroxidase
Implementation Method 5
The fluid is drawn into a capillary channel that extends in the test sensor from the testing end to the reagent material by capillary action
Data Source
AI summary
An electrochemical test sensor is adapted to measure glucose and correct for the oxygen effect in a fluid sample. The test sensor comprises a base, first and second working electrodes, and a counter electrode. The first working electrode includes glucose oxidase, a mediator and peroxidase. The second working electrode includes glucose oxidase and the mediator. The first working electrode, the second working electrode and the counter electrode are located on the base. In other embodiments, an electrochemical test sensor is adapted to measure cholesterol, lactate, pyruvate or xanthine and correct for the oxygen effect in a fluid sample.