Micro Biosensor Electrode Replenishment for Stable CGM Lifetime
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Solution Overview
Problem
Existing continuous glucose monitoring (CGM) biosensors face limitations in usage lifetime due to silver chloride depletion, leading to unstable measurements and increased implantation length, which results in patient discomfort and infection risks.
Innovation Solution
A micro biosensor system with a working electrode, counter electrode, and auxiliary electrode that cyclically applies measurement and replenishment potentials to maintain silver halide levels within a safe range, allowing for uninterrupted glucose monitoring and reducing the size and toxicity of the implantation end.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the counter electrode uses silver and silver chloride for stable measurement, then measurement reliability is improved, but silver chloride depletes over time causing usage lifetime to be limited
Solution Approach 1:
The patent implements a replenishment electrode that periodically regenerates silver chloride on the counter electrode through electrochemical reactions. This allows the consumed silver chloride to be recovered and replenished, extending the biosensor's usage lifetime while maintaining measurement reliability throughout the extended period
Solution Approach 2:
The biosensor system preliminarily includes a replenishment electrode and control circuitry designed to regenerate silver chloride before complete depletion occurs. This preliminary replenishment action prevents measurement instability and extends operational lifetime by maintaining adequate silver chloride levels throughout the usage period
2Duration of action of stationary object
If the counter electrode is made larger to increase silver chloride capacity, then usage lifetime is extended, but implantation length increases causing patient discomfort and infection risks
Solution Approach 1:
Instead of increasing electrode size to extend lifetime, the patent uses a replenishment mechanism that recovers silver chloride in place. This allows extension of usage lifetime without increasing implantation length, avoiding patient discomfort and infection risks associated with larger implants
Solution Approach 2:
The replenishment electrode enables the counter electrode to self-regenerate its silver chloride capacity through electrochemical reactions driven by the biosensor's power supply. This self-service capability extends lifetime without requiring a larger initial silver chloride reservoir, thus maintaining compact implantation dimensions
3Length of moving object
If the counter electrode is made smaller to reduce implantation size, then patient comfort is improved, but silver chloride depletes faster limiting usage lifetime
Solution Approach 1:
The replenishment electrode recovers and regenerates silver chloride on the compact counter electrode, allowing a smaller implantation size to achieve extended usage lifetime. The recovery mechanism compensates for the reduced initial silver chloride capacity of the smaller electrode
Solution Approach 2:
The self-replenishing capability allows the compact counter electrode to maintain adequate silver chloride levels throughout extended operation. This enables a smaller implantation size to achieve longer usage lifetime than would otherwise be possible with its limited initial capacity
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 extends the biosensor's usage lifetime, reduces biological toxicity, and minimizes patient discomfort by maintaining stable glucose monitoring over an extended period with a compact implantation end.
Implementation Method 1
a first oxidation reaction to occur on the working electrode having an electrochemical reaction with the chemical reagent and the analyte
Implementation Method 2
the working electrode has a higher voltage level than that of the counter electrode during a measurement period, for causing a first oxidation reaction to occur on the working electrode having an electrochemical reaction with the chemical reagent and the analyte
Implementation Method 3
a reduction reaction occurs on the corresponding reference electrode (R) or reference/counter electrode (R/C) to cause the AgCl to be reduced to Ag and the AgCl is consumed
Implementation Method 4
applying a replenishment potential difference across the counter electrode and the auxiliary electrode during a replenishment period so that the counter electrode has a higher voltage level than that of the auxiliary electrode, causing a second oxidation reaction to occur to the silver on the counter electrode
Data Source
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AI summary
The present invention provides a measuring method for prolonging a usage lifetime of the micro biosensor (300) to measure a physiological signal associated with an analyte. The micro biosensor (300) includes a working electrode (320), a counter electrode (330) including silver and a silver halide having an initial amount, and an auxiliary electrode (340). The method includes cyclic steps of: applying a measurement voltage to drive the working electrode (320) to measure the physiological signal, where the silver halide is consumed by a consumption amount; stopping applying the measurement voltage; and whenever the physiological parameter is obtained, applying a replenishment voltage between the counter electrode (330) and the auxiliary electrode (340) to drive the counter electrode (330), thereby the silver halide of a replenishment amount being replenished to the counter electrode (330), wherein a guarding value of a sum of the replenishment amount and the initial amount subtracting the consumption amount is controlled within a range of the initial amount plus or minus a specific value.