Implantable Electrode Grid Structure for Neural Stimulation Stability
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Solution Overview
Problem
Current electrode designs for neural stimulation, particularly in retinal prosthetics, face challenges with stability and current distribution due to edge effects and material thickness limitations, leading to tissue damage and short electrode lifespan.
Innovation Solution
The development of an electrode array with a clustered surface and grid structure, combined with electroplating and polymer filling techniques, enhances stability and adhesion by increasing the edge length and reducing stress, allowing for thicker metal layers and improved current distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If thin metal layers are used in electrodes, then the electrode can be flexibly implanted, but the electrode lacks stability and has short lifespan
Solution Approach 1:
The electrode employs a composite structure consisting of a flexible substrate combined with electroplated metal clusters arranged in a grid pattern. This composite design provides both the flexibility needed for implantation and the structural stability required for long-term operation, resolving the contradiction between flexibility and stability.
Solution Approach 2:
The metal layer is segmented into discrete clusters arranged in a grid pattern rather than forming a continuous thin layer. This segmentation allows each cluster to provide stable electrical contact while the overall structure remains flexible, addressing both stability and flexibility requirements.
2Stability of the object's composition
If thicker metal layers are used in electrodes, then the electrode gains stability and lifespan, but stress increases causing delamination
Solution Approach 1:
The metal is divided into discrete clusters rather than a continuous thick layer. This segmentation reduces internal stress accumulation while maintaining stable electrical contact points, allowing for sufficient metal thickness without causing delamination.
Solution Approach 2:
The electrode structure has varying local properties: metal clusters provide local stability and electrical contact, while the spaces between clusters and the flexible substrate provide stress relief. This local quality differentiation resolves the stress-stability contradiction.
3Use of energy by moving object
If edge effects are present in electrodes, then current distribution is concentrated at edges, but tissue damage occurs
Solution Approach 1:
The electrode surface features a grid pattern with spaces between metal clusters, creating a porous-like structure. This design distributes current across multiple edges and surfaces of the clusters rather than concentrating it at a single continuous edge, reducing tissue damage while maintaining effective current delivery.
Solution Approach 2:
The continuous edge is segmented into multiple discrete cluster edges. This segmentation distributes the current density across numerous smaller edges, preventing the harmful concentration of current at a single location and reducing tissue damage.
4Strength
If clustered surface structure is added to electrodes, then adhesion and stability improve, but manufacturing complexity increases
Solution Approach 1:
The manufacturing process replaces complex mechanical structuring with electrochemical deposition. By using electroplating to create the clustered metal structure on a flexible substrate, the process achieves strong adhesion and stable clustered geometry through chemical means rather than mechanical fabrication, simplifying manufacturing while maintaining structural integrity.
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 new electrode design achieves increased stability and prolonged lifespan by minimizing edge effects and stress, ensuring effective and chronic neural stimulation with improved adhesion and current distribution.
Implementation Method 1
electroplating and polymer filling techniques, enhances stability and adhesion
Data Source
AI summary
The present invention provides an implantable electrode with increased stability wherein the surface is of the electrode comprises mesh grids which are filled with sticks which are filed with a conducting or insulating material. The present invention further provides a method of manufacturing an electrode with increased stability, comprising: depositing a metal layer on an base layer; applying photoresist layer on the metal layer; patterning the photoresist layer providing openings; electroplating the openings with metal; removing the photoresist layer leaving spaces; and filling the spaces with polymer.