Implantable Micro-Biosensor Electrode Layout for Stable Glucose Sensing
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Solution Overview
Problem
Current implantable continuous glucose monitoring systems face challenges in accurately measuring glucose concentrations due to interference from substances like ascorbic acid, acetaminophen, uric acid, and protein, leading to instability and reduced service life of biosensors, particularly with silver/silver chloride electrodes which are consumed quickly, necessitating longer electrodes that increase implantation complications.
Innovation Solution
An implantable micro-biosensor design featuring a substrate with multiple electrodes and a chemical reagent layer, where the relative positioning of electrodes allows for selective measurement and regeneration of silver halide, reducing interference and extending sensor life by using a counter electrode to manage silver halide levels effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If the counter electrode length is increased to extend service life, then the biosensor can monitor glucose for longer periods, but the implantation becomes more complicated with larger wounds and higher infection risk
Solution Approach 1:
The counter electrode is divided into two separate electrodes (first and second counter electrodes) that can be positioned at different locations on the substrate. This segmentation allows the biosensor to achieve extended service life through distributed electrochemical reactions without requiring a single long electrode, thereby simplifying implantation geometry and reducing surgical complexity.
Solution Approach 2:
Instead of extending the counter electrode in one dimension (length), the patent distributes multiple counter electrodes across the substrate surface, utilizing two-dimensional spatial arrangement. This dimensional transition allows the system to achieve the required consumption capacity through area distribution rather than linear extension, avoiding the implantation complications associated with long electrodes.
2Measurement precision
If multiple working electrodes with different enzymes are used to filter interfering substances, then measurement accuracy improves, but the device complexity increases
Solution Approach 1:
The first and second counter electrodes are designed to perform multiple functions: they serve as counter electrodes for electrochemical reactions, and simultaneously function as interference-filtering electrodes through their distributed arrangement. This multi-functionality reduces the need for separate specialized electrodes, thereby simplifying the overall device structure while maintaining measurement accuracy.
Solution Approach 2:
The distributed counter electrodes act as intermediaries that facilitate both the electrochemical reactions necessary for measurement and the filtering of interfering substances. By positioning these electrodes strategically, the system achieves interference rejection without requiring additional specialized filtering components, thus reducing device complexity.
3Duration of action of moving object
If silver chloride is maintained at minimal amount to extend service life, then the biosensor operates longer, but the reference potential stability deteriorates
Solution Approach 1:
The patent changes the operational parameters of the silver/silver chloride electrodes by distributing multiple counter electrodes across the substrate. This parameter change allows the system to extend service life through distributed consumption while maintaining reference potential stability through the collective contribution of multiple electrodes, effectively decoupling the trade-off between duration and stability.
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 solution enables accurate and prolonged continuous glucose monitoring with reduced interference from interfering substances and extended service life, minimizing implantation complications and improving measurement accuracy.
Implementation Method 1
glucose is subjected to a catalysis reaction with glucose oxidase (GOx) to produce gluconolactone and a reduced glucose oxidase
Implementation Method 2
The glucose concentration is then derived from an oxidation reaction of the byproduct H2O2
Implementation Method 3
silver chloride would be even more consumed by reduction of silver chloride to silver
Data Source
AI summary
An implantable micro-biosensor a substrate, a first electrode, a second electrode, a third electrode, and a chemical reagent layer. The first electrode is disposed on the substrate and used as a counter electrode. The second electrode is disposed on the substrate and spaced apart from the first electrode. The third electrode is disposed on the substrate and used as a working electrode. The chemical reagent layer at least covers a sensing section of the third electrode so as to permit the third electrode to selectively cooperate with the first electrode or the first and second electrodes to measure a physiological signal in response to the physiological parameter of the analyte.