Smart Memory Polymer Nerve Cuff Electrodes for Small Nerves
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Solution Overview
Problem
Existing nerve cuff electrodes have limited ability to curve around small nerves, leading to incomplete stimulation and recording of neural activity, and suffer from fibrotic tissue ingrowth that increases electrode impedance and blocks functionality.
Innovation Solution
A nerve cuff electrode device with a smart memory polymer layer that transitions from a rigid configuration at room temperature to a softened configuration at body temperature, featuring discrete titanium nitride electrodes with high charge injection capacity and surface roughness, allowing close proximity to nerve surfaces and reducing scar tissue growth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If rigid polymer bodies (e.g., polyimide or parylene) are used for nerve cuff electrodes, then structural stability and ease of manufacture are improved, but the ability to curve around small nerves and achieve tight neural contact is worsened
Solution Approach 1:
The patent employs shape memory polymers that undergo parameter changes in response to temperature variations. The polymer transitions from a rigid state at room temperature (便于植入操作) to a softened state at body temperature (37°C), enabling the cuff to curve around and conform to small nerves with radii of 3000 microns or less, thereby resolving the contradiction between structural stability and curvature ability
Solution Approach 2:
The patent uses composite material structures combining shape memory polymer layers with thin film electrode layers. This composite approach integrates the temperature-responsive shape-changing capability of SMPs with the electrical functionality of thin film electrodes, achieving both structural adaptability and neural stimulation/recording functions
2Shape
If flexible polymer bodies (e.g., silicone) are used for nerve cuff electrodes, then the ability to curve around nerves is improved, but structural stability and manufacturing precision are worsened
Solution Approach 1:
The shape memory polymer provides temperature-dependent parameter changes that give the material rigid characteristics during implantation (for positioning stability) and flexible characteristics at body temperature (for conforming to nerve surfaces), thereby simultaneously achieving curvature ability and structural stability that flexible polymers alone cannot provide
3Ease of manufacture
If conventional electrode surfaces are used, then manufacturing simplicity is maintained, but charge injection capacity is limited
Solution Approach 1:
The patent employs porous titanium nitride electrode surfaces with controlled porosity (50-90% pore volume) and specific surface areas (0.03-0.1 cm²). The porous structure dramatically increases charge injection capacity (up to 10 times that of smooth surfaces) while maintaining compatibility with standard thin film deposition and patterning manufacturing processes
4Manufacturing precision
If smooth electrode surfaces are used, then manufacturing precision is maintained, but charge injection capacity and neural interface effectiveness are worsened
Solution Approach 1:
The patent utilizes porous titanium nitride surfaces created through controlled deposition conditions (e.g., sputtering parameters, deposition temperature) that produce consistent pore structures with defined surface areas. This approach achieves both manufacturing precision (reproducible pore geometry) and enhanced charge injection capacity (higher effective surface area for electrochemical reactions)
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 device achieves tight curvature around small nerves, enhances electrode proximity, and minimizes fibrotic tissue ingrowth, enabling effective stimulation and recording of neural activity with reduced impedance and improved biocompatibility.
Implementation Method 1
a smart memory polymer layer with a rigid configuration at room temperature and a softened configuration at about 37° C.
Implementation Method 2
An exposed surface of each of the discrete titanium nitride electrode sites has a charge injection capacity of about 0.1 mC/cm2 or greater.
Data Source
AI summary
A nerve cuff electrode device comprising a cuff body having a smart memory polymer layer with a rigid configuration at room temperature and a softened configuration at about 37° C. The smart memory polymer layer has a trained curved region with a radius of curvature of about 3000 microns or less. A plurality of thin film electrodes located on the smart memory polymer layer. The thin film electrodes include discrete titanium nitride electrode sites that are located in the trained curved region. An exposed surface of each of the discrete titanium nitride electrode sites has a charge injection capacity of about 0.1 mC/cm2 or greater. Methods or manufacturing and using the device are also disclosed.