Electrochemical Sensor Mediator Design for Low-Interference Analyte Detection
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Solution Overview
Problem
Existing electrochemical test devices face challenges in accurately measuring low concentrations of analytes like glycerol and β-hydroxybutyrate due to interference from electrochemically active interferents and the need for sensitive detection, particularly in healthy individuals where analyte levels are low.
Innovation Solution
The development of an electrochemical test device with a set of electrodes, including a first working electrode with lactate oxidase and a second working electrode with diaphorase, NAD(P)+-dependent dehydrogenase, and a cofactor, utilizing different electron transfer agents to achieve precise measurement of lactate and glycerol or β-hydroxybutyrate concentrations, with a counter/reference electrode having a third electron transfer agent to minimize interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If direct oxidation of NAD(P)H is used at carbon working electrode, then electron transfer is achieved, but large positive overpotential (0.55 V) causes interference from electrochemically active interferents
Solution Approach 1:
The patent employs a mediator with a lower standard redox potential than NAD(P)+ to facilitate electron transfer from NAD(P)H to the electrode. This mediator acts as an intermediary that accepts electrons from NAD(P)H and transfers them to the electrode at a lower potential, thereby avoiding the large positive overpotential (0.55 V) required for direct NAD(P)H oxidation and eliminating interference from electrochemically active interferents.
Solution Approach 2:
The patent changes the redox potential parameter by selecting a mediator with a lower standard redox potential than NAD(P)+. This parameter change allows the electron transfer reaction to occur at a lower potential, fundamentally altering the electrochemical conditions to avoid interferent oxidation while maintaining efficient electron transfer from NAD(P)H.
2Measurement precision
If sensitive detection is used for low concentration analytes, then measurement accuracy improves, but interference from other substances increases
Solution Approach 1:
The mediator serves as a selective intermediary that specifically facilitates electron transfer from NAD(P)H while having lower redox potential than interferents like ascorbic acid, uric acid, and acetaminophen. This selectivity allows sensitive detection of low concentration analytes by maintaining a potential window where the mediator reacts with NAD(P)H but interferents remain electrochemically inactive.
Solution Approach 2:
The patent creates a localized electrochemical environment at the electrode surface where the mediator concentration is high and the redox potential is controlled to match the mediator's characteristics. This local quality differentiation allows the electrode to selectively detect NAD(P)H-derived signals from low concentration analytes while excluding interferents that would otherwise be detected at higher potentials.
3Adaptability or versatility
If multiple analytes are measured simultaneously, then device versatility improves, but measurement precision for each analyte decreases
Solution Approach 1:
The patent implements a universal mediator system that can detect multiple analytes (glucose, lactate, glycerol, β-hydroxybutyrate) through their common enzymatic reactions producing NAD(P)H. The single mediator-based electrode provides multi-analyte capability while maintaining precision through selective potential control that targets the mediator's specific redox characteristics, enabling simultaneous or sequential measurement of different analytes without cross-interference.
Solution Approach 2:
The patent segments the detection process by using separate working electrodes, each optimized for specific analytes (e.g., glucose oxidase for glucose, lactate oxidase for lactate, dehydrogenases for glycerol and β-hydroxybutyrate), while all electrodes use the same mediator system. This segmentation allows each electrode to maintain high precision for its target analyte while the overall device achieves versatility through the common mediator platform.
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 configuration allows for accurate and sensitive determination of analyte concentrations, reducing interference and improving measurement reliability, especially for low-level analytes like glycerol and β-hydroxybutyrate, by utilizing distinct electron transfer agents and operational modes that enhance signal detection.
Implementation Method 1
The first analyte is lactate and the sensing chemistry for the lactate comprises lactate oxidase
Implementation Method 2
lactate oxidase and an electron transfer agent
Implementation Method 3
an electron transfer agent has a first standard redox potential... determining the concentration of the first analyte based on an output signal generated from the current
Implementation Method 4
The second working electrode is provided with second sensing chemistry for the second analyte. The second sensing chemistry comprises a diaphorase, an electron transfer agent, an NAD(P)+-dependent dehydrogenase
Implementation Method 5
NAD(P)+-dependent dehydrogenase... releasing NAD(P)+/NAD(P)H from active sites reversibly
Implementation Method 6
The counter/reference electrode is provided with a third electron transfer agent. The third electron transfer agent has a third standard redox potential. The third standard redox potential is higher than the second standard redox potential by at least 0.2 V
Data Source
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AI summary
An electrochemical test device for use in determining a concentration of each of a first analyte and a second analyte in a fluid sample is provided. The electrochemical test device comprises a set of electrodes including a first working electrode having sensing chemistry for the first analyte and a second working electrode having sensing chemistry for the second analyte, wherein the first analyte is lactate and the sensing chemistry for the lactate comprises lactate oxidase and an electron transfer agent, and wherein the sensing chemistry for the second analyte comprises a diaphorase, an electron transfer agent, an NAD(P)+-dependent dehydrogenase and a cofactor for the NAD(P)+-dependent dehydrogenase.