Glassy Carbon Neural Probe Homogeneity Eliminates Delamination
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Solution Overview
Problem
Conventional probes used for long-term implantation in the body are prone to delamination, tissue damage, and immune responses due to material incompatibility and structural weaknesses, leading to inaccurate measurements and ineffective therapies.
Innovation Solution
A glassy carbon probe with a homogeneous structure, comprising a glassy carbon layer and insulating layers without intermediate metal layers, is developed using a microfabrication process that includes pyrolysis and photolithography, providing enhanced biocompatibility and mechanical strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional probes with intermediate metal layers are used, then electrical conductivity is achieved, but delamination and tissue damage occur due to material incompatibility
Solution Approach 1:
The patent applies homogeneity by using a single glassy carbon material for both the probe body and the electrode, eliminating intermediate metal layers. This homogeneous structure prevents delamination between dissimilar materials and reduces tissue damage, as the glassy carbon maintains biocompatibility throughout the entire probe structure while providing both mechanical strength and electrical conductivity.
Solution Approach 2:
The patent employs composite materials by combining glassy carbon with insulating layers (such as parylene or polyimide) to create a functionally integrated probe. The glassy carbon provides structural integrity and electrical conductivity, while the insulating layers provide electrical isolation and biocompatibility, eliminating the need for separate metal interconnect layers that cause delamination.
2Reliability
If conventional probes with multiple intermediate layers are used, then electrical connections are established, but immune responses are triggered due to material incompatibility
Solution Approach 1:
The homogeneous glassy carbon structure eliminates interfaces between dissimilar materials that would otherwise trigger immune responses. The entire probe body and electrode are made from the same biocompatible glassy carbon material, preventing the formation of reactive interfaces that could initiate immune reactions in the surrounding tissue.
Solution Approach 2:
The patent extracts and removes the problematic intermediate metal layers from the probe structure. By eliminating these metal components that are known to trigger immune responses, the design achieves superior biocompatibility while maintaining electrical functionality through the glassy carbon material itself.
3Duration of action of stationary object
If probes with intermediate metal layers are used, then electrical conductivity is achieved, but structural weaknesses lead to failure during long-term implantation
Solution Approach 1:
The homogeneous glassy carbon structure eliminates weak interfaces between dissimilar materials where delamination would initiate. The uniform material properties throughout the probe body provide consistent mechanical strength and fatigue resistance, enabling long-term implantation without structural failure.
Solution Approach 2:
The composite structure of glassy carbon combined with flexible insulating layers creates a mechanically robust probe that can withstand long-term implantation. The glassy carbon provides compressive strength and chemical stability, while the insulating layers provide tensile flexibility, creating a composite that resists both delamination and mechanical failure over extended periods.
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 glassy carbon probe minimizes tissue damage and immune responses, maintains structural integrity during long-term use, and achieves accurate neural recordings and stimulation with improved mechanical and electrical properties.
Implementation Method 1
pyrolyzing the glassy carbon precursor to allow glassy carbon to form
Implementation Method 2
patterning the glassy carbon precursor using photolithography
Data Source
AI summary
A probe device is disclosed that includes one or more insulating layers and a glassy carbon layer. The glassy carbon layer includes one or more channels. Each channel includes a microstructure, which may include an electrode region, interconnect region, and bump pad region. The electrode region may be placed in contact with a human or animal patient or test subject and used to collect or deliver signals in applications such as electrocorticography (ECoG), electromyography (EMG), and neural stimulation. A method of making a probe includes depositing a glassy carbon precursor on a substrate, patterning the precursor using photolithography, pyrolyzing the precursor to allow the formation of glassy carbon, and depositing one or more insulating layers.