Bio-electrode with Localized Silicon Resin for Conductivity and Biocompatibility
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Solution Overview
Problem
Current bio-electrodes face challenges in achieving a balance between electric conductivity and biocompatibility, while also being lightweight and cost-effective, due to issues with skin allergies, high production costs, and limited durability when used for long-term monitoring of physical conditions like heart rate.
Innovation Solution
A bio-electrode design featuring a resin layer with particles coated in gold, platinum, or silver, where the resin layer's thickness is equal to or thinner than the particle size, and composed of both silicon-containing and non-silicon-containing resins, ensuring excellent conductivity and biocompatibility, with the silicon-containing resin localized on the surface for repellency and adhesion properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If water soluble gel containing water and electrolyte is used as electrode material, then electric conductivity is achieved, but electric conductivity is lost as water is lost due to drying
Solution Approach 1:
The patent changes the physical state of the electrode material from a water-based gel to a solid resin composite. This parameter change eliminates the drying issue while maintaining electric conductivity through the resin-particle composite structure, enabling long-term continuous monitoring without conductivity loss.
Solution Approach 2:
The patent creates a composite material consisting of resin (providing structural stability and preventing drying) and conductive particles (providing electric conductivity). This composite structure combines the advantages of both materials while eliminating their individual disadvantages, achieving both long-term durability and sustained conductivity.
2Reliability
If metal with high ionization tendency such as copper is used, then electric conductivity is improved, but skin allergies occur
Solution Approach 1:
The patent applies local quality by using noble metal particles (gold, platinum, silver) which have high conductivity and low allergenicity, dispersed within a resin matrix. This local distribution of conductive particles provides sufficient conductivity while the resin barrier prevents direct skin contact with potentially allergenic metals, eliminating skin allergy risks.
Solution Approach 2:
The resin acts as an intermediary material between the conductive particles and the skin. It allows electrical signals to pass through while preventing direct contact between skin and metal particles, thus eliminating the harmful effect of skin allergies while maintaining the useful effect of electric conductivity.
3Reliability
If electro-conductive polymer such as PEDOT-PSS is used, then electric conductivity is achieved, but skin allergies occur due to strong acidity
Solution Approach 1:
The patent uses chemically stable noble metal particles that do not degrade or release acidic substances over time. Unlike electro-conductive polymers that may decompose and cause skin irritation, these metal particles maintain their stability throughout the device's lifespan, eliminating the risk of acidity-induced skin allergies while providing consistent conductivity.
4Reliability
If metal nanowire or carbon nanotube is used, then electric conductivity is improved with small loading amount, but skin allergies occur due to thin material with sharp tips
Solution Approach 1:
The patent uses spherical or curved metal particles instead of thin, sharp nanowires or nanotubes. The rounded geometry eliminates sharp tips that could penetrate or irritate skin, while the spherical shape maintains good contact probability between particles for electrical conductivity. This shape modification removes the harmful effect while preserving the beneficial effect.
5Reliability
If carbon black is used, then electric conductivity is achieved with lower toxicity, but skin irritation occurs
Solution Approach 1:
The patent uses noble metal particles that replicate the conductive function of carbon black but without its irritating properties. The metal particles provide equivalent or superior conductivity while being chemically inert and non-irritating to skin, effectively copying the useful function while eliminating the harmful side effect.
6Reliability
If noble metal particles are loaded in volume ratio of 70% or more, then electric conductivity is achieved, but production cost becomes very high and weight increases
Solution Approach 1:
The patent changes the resin's electrical properties by selecting resins with higher intrinsic conductivity or by optimizing the particle-resin interface. This allows achieving sufficient overall conductivity with lower particle loading (well below 70% volume ratio), thereby reducing both weight and cost while maintaining the required electric conductivity performance.
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 efficiently conducts electric signals, reduces the risk of skin allergies, minimizes particle usage for lighter weight, and lowers production costs, while maintaining durability and repellency against perspiration and drying.
Implementation Method 1
the resin layer contains a silicon-containing resin and a non-silicon-containing resin; the silicon-containing resin is localized in the direction of a surface of the resin layer
Implementation Method 2
the silicon-containing resin is localized in the direction of a surface of the resin layer
Data Source
AI summary
The present invention provides a bio-electrode including an electro-conductive base material and a living body contact layer formed on the electro-conductive base material; wherein the living body contact layer contains a resin layer and particles dispersed in the resin layer, the particles being coated with gold, platinum, silver, or alloy of these metals; a thickness of the resin layer is equal to or thinner than an average particle size of the particles; the resin layer contains a silicon-containing resin and a non-silicon-containing resin; and the silicon-containing resin is localized in the direction of a surface of the resin layer. The bio-electrode of the present invention is superior in electric conductivity and biocompatibility, light in weight, can be manufactured at low cost, and can combine repellency of the resin layer surface and adhesion properties of the resin layer to particles.