3D Conductive Electrodes via Sacrificial Shell Filling
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Solution Overview
Problem
Current methods are inadequate for creating three-dimensional (3D) electrodes with micro-scale dimensions and complex geometries, such as self-intersecting paths, and struggle with achieving the necessary resolution and selective insulation or exposure of these electrodes.
Innovation Solution
A method involving the formation of a 3D shell with a hollow interior, filling it with an electrically conductive liquid, and causing the liquid to solidify within the shell, allowing for the creation of electrodes with intricate shapes and geometries, including self-intersecting designs, while enabling selective exposure or insulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If direct 3D printing with metal or conductive slurry is used, then free-standing metal structures can be produced, but the resolution and layer thickness are limited to 100 μm-150 μm
Solution Approach 1:
The fabrication process is segmented into distinct stages: forming a sacrificial mold structure, filling with conductive material, and selective removal of the mold. This segmentation allows each stage to be optimized independently, achieving micro-scale precision without requiring the entire process to operate at that resolution level.
Solution Approach 2:
A sacrificial mold material serves as an intermediary that enables the formation of complex 3D electrode geometries. The mold is easier to fabricate at lower resolutions, and its removal leaves behind the high-precision conductive electrode structure, effectively transferring the geometry from the mold to the final electrode.
2Ease of manufacture
If simple electrical traces or planar electrodes are formed, then fabrication is straightforward, but complex free-standing electrodes with non-rectilinear paths cannot be created
Solution Approach 1:
The invention transitions from 2D planar electrode fabrication to 3D free-standing structures by using a volumetric mold-filling approach. The sacrificial mold defines a 3D space that is filled with conductive material, enabling electrodes with spatial complexity in all three dimensions rather than being constrained to planar geometries.
Solution Approach 2:
The process changes the physical state and form of the conductive material from pre-formed traces to liquid slurry that can be poured and solidified. This parameter change allows the conductive material to conform to any 3D geometry defined by the mold, providing versatility in electrode design while maintaining fabrication simplicity.
3Shape
If folding techniques are used to transform 2D electronics into 3D electronics, then some 3D structures can be achieved, but the same resolution limitations and geometry constraints persist
Solution Approach 1:
Instead of folding 2D structures to create 3D forms, the invention inverts the approach by first creating a 3D sacrificial mold and then filling it with conductive material. This inversion allows the 3D geometry to be defined directly in the mold stage where lower precision is acceptable, rather than attempting to achieve micro-scale precision in the final electrode structure through folding.
4Manufacturing precision
If 3D electrodes are fabricated using existing techniques, then some electrodes can be produced, but selective insulation or exposure of specific electrode portions is challenging
Solution Approach 1:
The sacrificial mold can be designed with spatially varying properties, allowing different regions to be removed or retained after electrode formation. This local quality approach enables selective exposure or insulation of specific electrode portions by controlling which parts of the mold are removed, providing precise spatial control over electrode accessibility without adding complexity to the electrode fabrication itself.
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
This approach enables the fabrication of 3D electrodes with high resolution and complex geometries, improving their integration with cells and tissues, and allowing for precise electrical connectivity and measurement.
Implementation Method 1
causing the electrically conductive liquid to solidify within the 3D shell
Data Source
AI summary
A method for fabricating an electrode includes forming a 3D shell having a hollow interior and defining one or more openings, and directing an electrically conductive liquid through at least one of the one or more openings of the 3D shell, such that the 3D shell is at least partially filed with the electrically conductive liquid. The electrically conductive liquid can be caused to solidify within the 3D shell to form a solid electrode, or can remain a liquid to form a liquid electrode. The 3D shell can be formed having the one or more openings using a 3D printing process such as a two-photon writing system. The surface tension of the electrically conductive liquid aids in retaining the electrically conductive liquid within the 3D shell. The electrode can contact a tissue sample through one of the openings in the 3D shell.