Micro Biosensor Electrode Replenishment for Longer CGM Use
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Solution Overview
Problem
Existing continuous glucose monitoring (CGM) systems face limitations in the usage lifetime and size of biosensors due to silver chloride depletion, leading to unstable measurements and increased implantation pain and risk of infection, as they require larger electrode sizes and longer implantation lengths to maintain glucose monitoring for extended periods.
Innovation Solution
A micro biosensor with a replenishing technique that stabilizes silver chloride levels by alternating measurement and replenishment modes, using a chemical reagent to oxidize silver on the electrodes and replenish silver halide, allowing for uninterrupted glucose monitoring while reducing the size and toxicity of the sensor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If the counter electrode size is increased to provide sufficient silver chloride capacity for long-term monitoring, then the usage lifetime is extended, but the implantation size increases causing more pain and infection risk
Solution Approach 1:
The patent implements periodic action by alternating between measurement mode and replenishment mode. During replenishment mode, a reverse voltage is applied to regenerate silver chloride on the counter electrode surface, ensuring continuous availability of reactive material without requiring a large initial electrode size. This periodic regeneration enables long-term monitoring with a compact implantation design.
Solution Approach 2:
The patent applies parameter changes by dynamically adjusting the voltage polarity and magnitude between measurement and replenishment phases. During measurement, a first voltage promotes glucose oxidation and silver chloride consumption. During replenishment, a second reverse voltage regenerates silver chloride from metallic silver. This parameter switching enables the electrode to function with minimal initial silver chloride capacity while maintaining long operational lifetime.
2Reliability
If the counter electrode size is increased to maintain stable measurements over extended periods, then measurement stability is improved, but the sensor complexity and manufacturing cost increase
Solution Approach 1:
The patent implements self-service by enabling the counter electrode to automatically replenish its own silver chloride capacity through electrochemical regeneration. The electrode uses the body's natural chloride ions and applied reverse voltage to convert consumed metallic silver back into silver chloride, eliminating the need for external refilling or complex replacement mechanisms. This self-regenerating capability ensures measurement stability without increasing structural complexity.
3Duration of action of moving object
If silver chloride capacity is increased to prevent depletion during long-term use, then the usage lifetime is extended, but the biological toxicity increases
Solution Approach 1:
By implementing periodic measurement and replenishment cycles, the patent maintains a small, controlled amount of silver chloride on the counter electrode surface rather than loading a large initial capacity. This periodic regeneration approach ensures that only minimal silver chloride is present at any given time, reducing potential biological toxicity while extending operational lifetime through repeated regeneration cycles using biocompatible chloride ions from body fluids.
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 prolongs the usage lifetime of the biosensor, miniaturizes the implantation end, reduces biological toxicity, and decreases manufacturing costs, enabling continuous glucose monitoring for extended periods with reduced pain and risk of infection.
Implementation Method 1
a chemical reagent to oxidize silver on the electrodes and replenish silver halide
Implementation Method 2
the electrochemical reaction occurs so that the glucose oxidase (GOx) catalyzes the glucose to react and produce the gluconolactone and the reduced enzyme
Implementation Method 3
the glucose oxidase (GOx) catalyzes the glucose to react
Implementation Method 4
the reduced enzyme transfers electrons to the oxygen in the biofluid in the living body to produce a product hydrogen peroxide
Data Source
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AI summary
The present invention provides a measuring method for prolonging a usage lifetime of a micro biosensor (100) implanted subcutaneously to measure a physiological signal associated with an analyte. The micro biosensor (100) includes a working electrode (120) and a counter electrode (130), wherein the counter electrode (130) includes silver and a silver halide having an initial amount. The method includes cyclic steps of: applying a measurement voltage to drive the working electrode (120) to measure the physiological signal, where the silver halide is consumed by a specific amount; stopping applying the measurement voltage; and whenever the physiological parameter is obtained, applying a replenishment voltage to drive the counter electrode (130), thereby the silver halide of a replenishment amount being replenished to the counter electrode (130), 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.