High-Resistivity Nanofiber Electrode Contact for MRI Safety
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Solution Overview
Problem
Implantable medical devices, such as deep brain stimulators, face safety restrictions during MRI scans due to RF heating issues caused by metallic electrodes acting as antennas in the MRI magnetic field, leading to potential harm from excessive temperature increases.
Innovation Solution
An implantable biological electrode with a conductive non-magnetic nanofiber or film contact of specific resistivity (>10−6 Ω·m) is used, wound around a sleeve to form an electrical connection with the wire, reducing turbulence and heat induction by minimizing induced current transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a metallic electrode is used for electrical stimulation, then good electrical conductivity is achieved, but RF heating and turbulence occur during MRI scans
Solution Approach 1:
The patent changes the electrical resistivity parameter of the electrode contact from low (metallic) to high (≥10^-6 Ω·m) to reduce RF current induction during MRI scans. This parameter change transforms the electrode material properties to minimize turbulent heating while maintaining sufficient conductivity for neural stimulation through optimized geometry and material composition.
Solution Approach 2:
The patent employs composite material structures combining non-magnetic nanofibers (such as carbon nanotubes) with conductive polymers or metallic coatings. This composite approach achieves a balance between high electrical conductivity for stimulation and high resistivity to suppress RF heating, creating a multi-functional contact structure that addresses both requirements simultaneously.
2Reliability
If the electrode contact area is increased to improve stimulation effectiveness, then better electrical contact is achieved, but turbulence and heating are exacerbated
Solution Approach 1:
The patent applies local quality by creating non-uniform resistivity distribution within the contact structure. The nanofiber composite material provides locally optimized electrical properties where high resistivity regions suppress RF heating while maintaining sufficient conductivity for stimulation current flow, achieving spatially differentiated functionality within the contact area.
Solution Approach 2:
The patent transitions from traditional two-dimensional planar contacts to three-dimensional nanofiber composite structures. This dimensional change increases the effective contact surface area and volume for reliable stimulation while the porous nanofiber architecture provides air gaps and reduced current density paths that minimize RF heating, effectively decoupling contact area from heating risk.
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 high-resistivity nanofiber or film contact effectively suppresses turbulence and heat generation during MRI, enhancing the safety of the electrode and allowing for safer MRI procedures without compromising conductivity for electrical stimulation.
Implementation Method 1
The contact comprises a conductive non-magnetic nanofiber with a specific resistivity or a conductive film with a specific centre resistivity
Implementation Method 2
as the electrode acting as an antenna in the RF field, the electric field induced on the electrode will cause heating at the contact
Implementation Method 3
heating mainly occurs at the tip of the metallic implant... the electrode can avoid resonance of a MRI magnetic field so as to avoid over-heating
Data Source
AI summary
An implantable biological electrode, including a wire (2), wherein two ends of the wire (2) are connected with a contact (1) and a connector (3) respectively. The contact (1) comprises a conductive non-magnetic nanofiber with a specific resistivity or a conductive film with a specific center resistivity. A medical assembly comprises the implantable biological electrode. A contact prepared by the winding of a nanofiber or film material with a relatively high resistivity can effectively suppress turbulence and improve the safety of the electrode during magnetic resonance imaging.