Crosslinked Bio-Electrode Composition for Wet-Skin Signal Stability
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Solution Overview
Problem
Current bio-electrodes for wearable medical devices face challenges such as loss of conductivity when exposed to water, skin irritation, and limited durability, especially when used for long-term monitoring of biological signals.
Innovation Solution
A bio-electrode composition comprising a π-conjugated polymer combined with a dopant polymer containing hydroxy and carboxy groups, and a crosslinking agent, which forms a stable electro-conductive film that maintains conductivity and biocompatibility even when wet or attached to the skin for extended periods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hydrated gel is used as bio-electrode material, then conductivity is achieved, but the gel dries out and loses conductivity over time
Solution Approach 1:
The patent changes the physical and chemical parameters of the electrode material from hydrated gel to a solid polymer electrolyte composite. This involves changing the state from liquid-containing to solid-state, and modifying the chemical composition by incorporating specific polymer electrolytes with controlled ion conductivity, thereby achieving long-term stability without drying out
Solution Approach 2:
The patent uses a composite material system consisting of solid polymer electrolyte, conductive filler particles, and flexible polymer matrix. This composite structure combines the advantages of ionic conductivity from the polymer electrolyte, electrical conductivity from the filler, and mechanical flexibility from the matrix, solving the contradiction between maintaining conductivity and ensuring durability
2Reliability
If hydrated gel is used as bio-electrode material, then conductivity is achieved, but the gel swells during bathing and falls off
Solution Approach 1:
The patent changes the material state from gel to solid polymer electrolyte composite, eliminating the swelling issue by removing the liquid water component that causes volume expansion. The solid-state structure maintains dimensional stability while preserving ionic conductivity through the polymer matrix
Solution Approach 2:
The composite structure with crosslinked polymer matrix provides structural stability and adhesion to the substrate, preventing the electrode from falling off during bathing. The conductive filler particles maintain electrical pathways within the stable matrix structure
3Illumination intensity
If PEDOT-PSS is used for transparent conductive film, then transparency is improved, but the polymer disperses in water and falls off
Solution Approach 1:
The patent creates a composite material system where transparent conductive polymer is combined with water-resistant crosslinking agents and protective coating materials. This composite structure maintains the transparency of the polymer while the crosslinked network and protective layers prevent water penetration and material dispersion
Solution Approach 2:
The patent introduces intermediary substances such as crosslinking agents and adhesion promoters that mediate between the transparent polymer and the substrate. These intermediaries form a stable interface that prevents water from causing the polymer to detach, while maintaining optical transparency
4Reliability
If conventional bio-electrode materials are used, then conductivity is achieved, but skin irritation and allergy occur during long-term use
Solution Approach 1:
The patent changes the chemical composition parameters of the electrode material by selecting biocompatible polymer electrolytes and non-irritating conductive fillers. The material parameters are optimized to ensure pH neutrality, non-toxicity, and hypoallergenic properties while maintaining sufficient ionic and electrical conductivity for medical monitoring applications
Solution Approach 2:
The composite material system uses biocompatible components including medical-grade polymer electrolytes, inert conductive fillers, and hypoallergenic binding agents. This carefully selected composite formulation eliminates skin irritation and allergic reactions while preserving the necessary electrochemical performance for long-term wearable monitoring
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 bio-electrode composition ensures high sensitivity to biological signals, excellent biocompatibility, and durability, preventing skin irritation and maintaining conductivity, making it suitable for long-term use in wearable medical devices.
Implementation Method 1
a dopant polymer containing a repeating unit-a1 having a hydroxy group and/or a carboxy group
Implementation Method 2
a crosslinking agent
Implementation Method 3
converts changes of the concentration of ions from skin into electric signals by a reduction reaction of silver chloride contacting the hydrophilic gel
Data Source
AI summary
The present invention is a bio-electrode composition containing: an electro-conductive polymer composite including (A) a π-conjugated polymer and (B) a dopant polymer containing a repeating unit-a1 having a hydroxy group and/or a carboxy group and a repeating unit-a2 having a sulfonic acid, fluorosulfonimide, and N-carbonyl-fluorosulfonamide, the dopant polymer having a weight-average molecular weight of 1,000 to 500,000; and (C) a crosslinking agent. This provides: a bio-electrode composition that allows a thin film of high transparency, has high sensitivity to biological signals, has excellent biocompatibility, is light-weight, can be manufactured at low cost, can control significant reduction in sensitivity to biological signals when soaked in water for a long time or when attached to the skin for a long time, causes no itchiness, red spots, rashes, etc. of the skin, and is comfortable; a bio-electrode; and a method for manufacturing a bio-electrode.