Implantable Micro-Biosensor Electrode Layout for Longer CGM Life
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Solution Overview
Problem
Existing 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 stationary object
If the counter electrode length is increased to reduce silver chloride consumption, then the service life is extended, but the implantation complexity and infection risk increase
Solution Approach 1:
The counter electrode is divided into two functional sections: a first section with silver/silver chloride material for electrochemical reactions and a second section without this material that serves purely as current collection. This segmentation allows the electrode to be shorter while maintaining adequate silver chloride capacity, reducing implantation complexity and infection risk while preserving service life.
Solution Approach 2:
Different sections of the counter electrode have different material compositions and functions. The first section contains silver/silver chloride for active electrochemical participation, while the second section lacks this material and serves only for current collection. This local differentiation optimizes the distribution of silver chloride, reducing total consumption and enabling shorter electrode length.
2Measurement precision
If interfering substances are filtered out using polymer membrane, then measurement accuracy is improved, but the filtering completeness remains difficult to achieve
Solution Approach 1:
A polymer membrane is introduced as an intermediary layer between the biological fluid and the electrochemical sensing elements. This membrane selectively filters interfering substances while allowing glucose and other analytes to pass through, improving measurement accuracy by preventing direct interference with the electrochemical reactions.
Solution Approach 2:
The biosensor employs composite material structures including polymer membranes combined with electrochemical sensing layers. The polymer membrane provides selective filtration properties while the electrochemical materials enable accurate detection, creating a composite system that achieves both filtering effectiveness and measurement precision.
3Measurement precision
If multiple working electrodes with different enzymes are used to eliminate interference, then measurement accuracy is improved, but the device complexity increases
Solution Approach 1:
The counter electrode is designed to perform multiple functions: it serves as the cathode for hydrogen peroxide detection, provides current collection for the enzymatic reaction at the working electrode, and includes a current blocking layer to prevent unwanted electrochemical reactions. This multi-functionality reduces the need for additional separate components, simplifying the overall device structure while maintaining measurement accuracy.
Solution Approach 2:
Multiple functional layers and electrodes are integrated into a compact structure where the counter electrode incorporates both the active silver/silver chloride section and the current collection section. The current blocking layer is merged with the counter electrode structure, and the polymer membrane encompasses multiple sensing elements, creating a consolidated design that reduces device complexity.
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, long-term 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, followed by an electron transfer reaction between the reduced glucose oxidase and oxygen in a biological fluid of the body to produce hydrogen peroxide (H2O2) as a byproduct
Implementation Method 2
The glucose concentration is then derived from an oxidation reaction of the byproduct H2O2
Implementation Method 3
followed by an electron transfer reaction between the reduced glucose oxidase and oxygen in a biological fluid of the body to produce hydrogen peroxide (H2O2) as a byproduct
Implementation Method 4
stable sensing potentials can be obtained by using a silver/silver chloride as a material of the reference electrode or the counter/reference electrode
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.