Electrochemical Biosensor with Segmented Electrodes
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Solution Overview
Problem
Conventional miniaturized electrochemical systems for monitoring analytes in patient samples face challenges due to high resistivity in Ag/AgCl counter electrodes, leading to reduced sensitivity and accuracy, especially in samples with high analyte concentrations, and the use of single reagent layers that do not optimize the environment for each electrode.
Innovation Solution
The development of electrochemical sensor strips with independently optimized electrodes, where the working electrode has an oxidoreductase enzyme and a mediator, and the counter electrode has a soluble redox species, allowing for separate reagent layers to enhance conductivity and sensitivity, with the soluble redox species being present in a higher molar amount than its counterpart to facilitate optimal electrochemical reactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a combination counter/reference electrode made of Ag/AgCl is used, then the electrode exhibits stable electrochemical properties, but the high resistivity of Ag/AgCl material inhibits its capacity for carrying electrical current
Solution Approach 1:
The patent separates the counter electrode and reference electrode functions into distinct electrodes. The counter electrode is made of low-resistivity material (silver or aluminum) to handle high current, while the reference electrode uses Ag/AgCl for stable potential. This segmentation allows each electrode to be optimized for its specific function without compromise.
Solution Approach 2:
Different materials are used for different electrodes based on their specific functional requirements. The counter electrode uses highly conductive silver or aluminum for current carrying, while the reference electrode uses Ag/AgCl for potential stability. Each electrode has locally optimized material properties matched to its role in the electrochemical cell.
2Ease of manufacture
If a single reagent layer is used over both working and counter electrodes, then manufacturing is simplified, but the individual environment of each electrode is not controlled to provide optimum conditions for electrode function
Solution Approach 1:
The patent applies separate reagent layers to the working electrode and counter electrode. The working electrode receives reagents optimized for analyte detection (enzymes, mediators), while the counter electrode receives reagents optimized for current carrying and electrochemical stability. This segmentation enables independent optimization of each electrode's chemical environment.
Solution Approach 2:
Different reagent compositions are applied to different electrodes based on their specific functional needs. The working electrode environment is optimized for the analyte reaction, while the counter electrode environment is optimized for electrochemical stability and current handling. Each electrode has a locally tailored reagent layer.
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 design improves the sensitivity and accuracy of analyte concentration measurements, extends the range of analysis, and increases the shelf life of the sensor strips by maintaining a stable electrochemical environment and ensuring consistent current measurement across varying analyte concentrations.
Implementation Method 1
the oxidation or reduction half-cell reaction involving the analyte either produces or consumes electrons
Implementation Method 2
mediators or other substances that help to transfer electrons between the oxidation-reduction reaction and the working electrode
Implementation Method 3
A chemical reaction also occurs at the counter electrode, and this reaction is of the opposite type (oxidation or reduction) relative to the type of reaction at the working electrode
Data Source
AI summary
An electrochemical sensor strip has a base and a first electrode and a second electrode on the base. An oxidoreductase enzyme and a mediator are on the first electrode, and a soluble redox species is on the second electrode. The soluble redox species may be an organotransition metal complex, a transition metal coordination complex, an electroactive organic molecule, or mixtures thereof.