Electrospun Fibrous Matrix for Medical Electrical Lead Electrode Coating

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Solution Overview

Problem

Conventional medical electrodes face challenges in controlling tissue ingrowth, inflammation, and reduced electrode performance over time due to polarization and impedance issues at the electrode/tissue interface, making it difficult to extract and maintain optimal electrical performance.

Innovation Solution

A medical electrical lead with a fibrous matrix composed of poly(vinylidene fluoride-co-hexafluoropropene) (PVDF HFP) or other non-conductive polymers, such as polyurethane, is coated over the electrode using electrospinning or meltblowing techniques, with controlled fiber diameters and spacing to manage tissue ingrowth and maintain electrical performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional materials are used as electrodes, then electrode performance can be maintained initially, but tissue in-growth, inflammation, and fibrous scar tissue formation occur over time leading to reduced performance and difficulty in extraction

Engineering Contradiction:

Improveelectrode performanceVSAvoidlong-term electrode functionality

Core Design Contradiction:

ReliabilityVSDuration of action of moving object

Solution Approach 1:

A fibrous matrix is applied to the electrode surface before implantation to preemptively control tissue interaction. The matrix is pre-formed with specific fiber diameter (50-500 nm) and porosity characteristics that are designed to guide tissue ingrowth patterns and reduce inflammatory response before the implantation process begins

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The fibrous matrix modifies the physical and chemical parameters of the electrode-tissue interface by introducing controlled porosity (40-80% void space), specific surface area, and fiber diameter parameters. These parameter changes create a more favorable environment for tissue integration while maintaining electrical performance characteristics

Inventive Principle:

Principle #35Parameter changes

2Object-affected harmful factors

If a coating is applied to control tissue in-growth, then extraction difficulty may increase, but the coating must remain thin enough to maintain electrical performance

Engineering Contradiction:

Improvetissue in-growth controlVSAvoidelectrical performance

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The fibrous matrix provides locally optimized properties at the electrode-tissue interface, with different regions of the matrix having tailored fiber diameters, porosity, and material composition. This local quality variation allows control of tissue ingrowth in specific areas while maintaining electrical contact in other regions

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The fibrous matrix is designed with high porosity (40-80% void space) and interconnected pore structures that allow electrical signals to penetrate through the coating to reach the underlying electrode. The porous structure enables tissue ingrowth control while maintaining electrical performance by allowing field penetration and ionic conduction

Inventive Principle:

Principle #31Porous materials

3Object-affected harmful factors

If fiber diameter is reduced to control tissue in-growth, then manufacturing precision requirements increase, but larger fibers may allow better electrical signal transmission

Engineering Contradiction:

Improvetissue in-growth controlVSAvoidfiber diameter control

Core Design Contradiction:

Object-affected harmful factorsVSManufacturing precision

Solution Approach 1:

Traditional mechanical fiber formation methods are replaced with electrospinning technology, which uses electrical fields to draw and deposit polymer fibers. This substitution enables precise control of fiber diameter (50-500 nm) through electrical parameter control rather than mechanical constraints, achieving the required manufacturing precision

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The manufacturing process controls fiber diameter by adjusting multiple parameters including polymer solution concentration, electrical field strength, deposition distance, and solvent evaporation rate. These parameter changes enable precise control of fiber dimensions while maintaining manufacturing feasibility

Inventive Principle:

Principle #35Parameter changes

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 fibrous matrix improves tissue ingrowth control, reduces extraction force, and maintains electrophysiological therapy delivery without significantly impacting impedance, enhancing the longevity and effectiveness of the electrode.

Implementation Method 1

forming a fibrous matrix including a non-conductive polymer by electrospinning

Methodology Applied

Scientific EffectElectrospinning: Electrohydrodynamics

Implementation Method 2

forming a fibrous matrix including a non-conductive polymer by electrospinning or meltblowing

Methodology Applied

Scientific EffectMeltblowing: Melting

Data Source

PatentUS8903506B2Method for coating devices using electrospinning and melt blowing

Publication Date: 2014.12.02 CARDIAC PACEMAKERS INC

AI summary

A medical electrical lead may include an insulative lead body, a conductor disposed within the insulative lead body, an electrode disposed on the insulative lead body and in electrical contact with the conductor and a fibrous matrix disposed at least partially over the electrode. The fibrous matrix may be formed from a non-conductive polymer.