Fluid-Actuated Microelectrode Hardness Matching

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Solution Overview

Problem

Current neural microelectrodes face challenges in implantation due to the hardness mismatch between silicon-based electrodes and brain tissue, leading to immune responses and inflammation, while flexible electrodes are too soft for direct insertion.

Innovation Solution

A microelectrode with a flexible substrate that contains a cavity structure capable of holding a fluid, altering its hardness from being more rigid for implantation to soft and ductile for coexistence with brain tissue, utilizing a conductive layer and a method involving fluid injection and release for improved implantation and biocompatibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If silicon-based rigid electrodes are used for neural recording, then electrical signal collection capability is improved, but immune response and inflammation increase due to hardness mismatch with brain tissue

Engineering Contradiction:

Improveelectrical signal collection capabilityVSAvoidimmune response and inflammation

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The electrode substrate incorporates a cavity structure that can dynamically change its mechanical properties by filling or emptying the cavity with fluid. When the cavity is empty, the substrate is soft and flexible for implantation; when filled, it becomes rigid for stable signal recording, thus dynamically adapting to different operational requirements

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the physical state parameter of the substrate by controlling the fluid pressure within the cavity. By adjusting the pressure, the substrate transitions between soft and hard states, enabling it to match the mechanical properties of brain tissue while maintaining electrical functionality

Inventive Principle:

Principle #35Parameter changes

2Object-affected harmful factors

If flexible substrate is used to reduce immune response, then biocompatibility is improved, but implantation difficulty increases due to excessive softness

Engineering Contradiction:

Improveimmune responseVSAvoidimplantation ease

Core Design Contradiction:

Object-affected harmful factorsVSEase of operation

Solution Approach 1:

The electrode system dynamically adjusts its mechanical stiffness by controlling fluid pressure in the cavity. During implantation, the cavity is empty making the substrate soft and flexible for easy insertion. After implantation, fluid is injected to increase rigidity for stable positioning and signal recording

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The cavity structure is pre-designed within the substrate before implantation. This preliminary structural preparation allows the substrate to be compressed or deformed easily during insertion, and then maintain its shape and position once fluid is injected after implantation

Inventive Principle:

Principle #10Preliminary action

3Strength

If fluid is injected into cavity structure, then substrate hardness is increased for stable implantation, but device complexity increases due to fluid injection and release mechanism

Engineering Contradiction:

Improvesubstrate hardnessVSAvoidfluid control mechanism complexity

Core Design Contradiction:

StrengthVSDevice complexity

Solution Approach 1:

The complex fluid control system is separated from the electrode substrate itself. The cavity structure is integrated into the substrate, but the fluid injection and release mechanisms are external systems that interact with the electrode through simple openings or ports, thus extracting the complexity from the core electrode design

Inventive Principle:

Principle #2Taking out (Extraction)

4Adaptability or versatility

If cavity structure is added to substrate, then hardness adjustability is improved, but manufacturing precision requirements increase

Engineering Contradiction:

Improvehardness adjustabilityVSAvoidcavity structure precision

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The cavity structure creates a porous or hollow architecture within the substrate. This porous design allows fluid to be contained and pressurized, enabling mechanical property adjustment. The porous structure can be manufactured using standard microfabrication techniques without requiring extremely tight tolerances

Inventive Principle:

Principle #31Porous materials

Data Source

PatentUS20220225921A1Microelectrode, occluding device, microelectrode system, method for manufacturing microelectrode, and method for using microelectrode

Publication Date: 2022.07.21 TSINGHUA UNIVERSITY

AI summary

A microelectrode, a method for manufacturing the microelectrode, a method for using the microelectrode, an occluding device, and a microelectrode system are provided. The microelectrode (10) includes a substrate (110) and a conductive layer (120) on the substrate (110), and the conductive layer (120) is configured to conduct an electrical signal. The substrate (110) is a flexible substrate and includes a cavity structure (111), and the cavity structure (111) is configured to contain or release a fluid. The hardness of the substrate (110) in the case where the cavity structure (111) contains the fluid is different from the hardness of the substrate (110) in the case where the cavity structure (111) does not contain the fluid. The microelectrode has good ductility and stable electrical performance, and the microelectrode is easy to be implanted into the biological tissue and not easy to result in the immune reaction of the biological tissue.