Concave Microelectrode Coating Protection
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Solution Overview
Problem
Ablation probes with microelectrodes face challenges in maintaining an impedance-reducing polymer coating due to rubbing against the delivery sheath during insertion, leading to signal interference and reduced effectiveness.
Innovation Solution
The outer microelectrode surfaces are made concave to reduce convexity and minimize contact with the sheath, and an electrically-insulative rim is used to protect the coating, ensuring it remains intact during deployment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the microelectrode outer surface is convex, then the polymer coating can be applied effectively, but the coating gets rubbed off during insertion through the delivery sheath
Solution Approach 1:
The patent inverts the conventional convex outer surface of the microelectrode to a concave surface. This inversion changes the contact mechanics during insertion, allowing the microelectrode to nestle into the delivery sheath rather than rubbing against it, thereby protecting the polymer coating from friction damage while maintaining effective coating application on the concave surface
2Object-affected harmful factors
If the microelectrode surface is made concave, then contact with the sheath is reduced, but the coating application process becomes more difficult
Solution Approach 1:
The patent modifies the geometric parameters of the microelectrode surface by creating a controlled concave curvature with specific radius and depth parameters. This parameter optimization ensures that the concave surface is sufficiently curved to reduce sheath contact during insertion, yet maintains a geometry that allows uniform polymer coating application through standard electrochemical or dip-coating processes
3Object-affected harmful factors
If a smooth distal tip profile is maintained, then trauma to tissue is reduced, but the microelectrode coating cannot be protected during insertion
Solution Approach 1:
The patent segments the distal tip structure by distinguishing between the overall smooth external profile and the localized concave microelectrode surfaces. The concave geometry is confined to the microelectrode outer surfaces while the broader distal tip maintains a smooth contour for tissue compatibility, creating a multi-scale structural solution that simultaneously achieves tissue safety and coating protection
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 design effectively prevents the polymer coating from being rubbed off, maintaining signal integrity and ensuring consistent impedance reduction for effective tissue ablation.
Implementation Method 1
a second layer is disposed so that, when brought into contact with tissue, the second layer has a reduced impedance for transferring electrical signals to or from the tissue
Implementation Method 2
The microelectrodes are electrochemically polymerized with a conductive polymer, such as poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS)
Implementation Method 3
a conductive polymeric coating that coats the outer surface
Data Source
AI summary
An apparatus includes a tube, a tip electrode coupled to a distal end of the tube and shaped to define at least one cavity, a microelectrode disposed within the cavity and including an outer surface that is of lesser convexity than that of a portion of the tip electrode surrounding the cavity, and a conductive polymeric coating that coats the outer surface. Other examples are also described.