Hydrophilic Coating for Medical Devices via Radical Polymerization

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Solution Overview

Problem

Current hydrophilic coatings for medical devices face challenges such as particulation, delamination, and toxicity due to the migration of hydrophilic polymers, which can lead to reduced durability and increased health risks, and require complex solvent removal processes.

Innovation Solution

A hydrophilic coating comprising a cross-linked copolymer formed by radical polymerization of components A, B, and optional C and D, where A includes C2-C16 hydrophilic monomers with alkene and/or alkyne groups, B includes hydrophilic polymers with multiple alkene and/or alkyne groups, and D includes low molecular weight cross-linking agents, covalently attached to the substrate surface, reducing particulation and enhancing durability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If hydrophilic polymers are physically entrapped within an IPN network, then the coating provides necessary adherence to the substrate, but the hydrophilic polymer may migrate out of the IPN over time causing particulation and loss of hydrophilicity

Engineering Contradiction:
Improvecoating adherenceVSAvoidparticulation
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent extracts the harmful migration issue by transitioning from physical entrapment to chemical bonding. The hydrophilic polymer is covalently bonded to the substrate through radical polymerization, eliminating the migration pathway that causes particulation while maintaining adherence functionality.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent creates a composite coating system combining cross-linked polymer network with covalently bonded hydrophilic polymer. This composite structure provides both the mechanical adherence of the cross-linked network and the hydrophilic properties of the bonded polymer, preventing migration while maintaining functionality.

Inventive Principle:
Principle #40Composite materials

2Object-generated harmful factors

If hydrophilic polymers are chemically bonded to the coating, then particulation is minimized, but the coating may be delaminated or detached from the substrate

Engineering Contradiction:
ImproveparticulationVSAvoidcoating durability
Core Design Contradiction:
Object-generated harmful factorsVSReliability

Solution Approach 1:

The patent extracts the delamination risk by using cross-linked polymer networks that form integral parts of the substrate structure. The radical polymerization creates strong covalent bonds between the coating and substrate, eliminating the detachment pathway while maintaining minimal particulation through chemical bonding.

Inventive Principle:
Principle #2Taking out (Extraction)

3Ease of manufacture

If organic solvents are used to prepare hydrophilic coatings, then the coating can be formed with desired properties, but residual traces must be removed to be below toxic limits

Engineering Contradiction:
Improvecoating formationVSAvoidsolvent removal process
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent changes the fundamental parameter of the coating system from organic solvent-based to water-based or solvent-free radical polymerization. This parameter change eliminates the need for complex solvent removal processes while maintaining the ability to form coatings with desired hydrophilic and adherent properties.

Inventive Principle:
Principle #35Parameter changes

4Ease of operation

If the coating is made highly hydrophilic and lubricious, then friction is reduced and protein adhesion is resisted, but the coating becomes more susceptible to erosion and delamination

Engineering Contradiction:
ImprovelubricityVSAvoidcoating stability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent creates a composite structure where hydrophilic polymers providing lubricity are covalently bonded to a cross-linked polymer network that provides mechanical stability. This composite approach allows the coating to be highly hydrophilic and lubricious while resisting erosion and delamination through the strong covalent bonding and cross-linked structure.

Inventive Principle:
Principle #40Composite materials

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 coating is highly lubricious, stable to sterilization and aging, biocompatible, and low particulating, with improved adhesion to the substrate, ensuring patient safety and device performance.

Implementation Method 1

Lubricious coatings are particularly useful for intracorporeal devices where their lubricity results in reduced frictional forces once a device is introduced and moved within the body

Methodology Applied
Scientific EffectLubrication: Lubrication

Implementation Method 2

As well as reducing friction, hydrophilic coatings also tend to be resistant to protein adhesion, therefore they have the potential to reduce or eliminate thrombosis

Methodology Applied
Scientific EffectHydrophilic interaction: Hydrophile

Data Source

PatentEP2950832B1Coating for substrate
Publication Date: 2018.08.01 WL GORE & ASSOC INC
  • EP2950832B1 patent drawingFigure 1~2
  • EP2950832B1 patent drawingFigure 3A~3E
  • EP2950832B1 patent drawingFigure 4~5

AI summary

There is provided inter alia a substrate with a surface having a hydrophilic coating comprising a cross-linked copolymer of components A and B, and optional components C and D; wherein component A comprises one or more C2-C16 hydrophilic monomers each bearing one or more alkene and/or alkyne groups; component B comprises one or more hydrophilic polymers each bearing two or more alkene and/or alkyne groups; component C, if present, comprises one or more beneficial agents each bearing one or more alkene or alkyne groups; and component D, if present, comprises one or more low molecular weight cross-linking agents each bearing two or more functional groups independently selected from thiol, alkene and alkyne groups; wherein the cross-linked copolymer is formed by radical polymerisation involving the alkene and/or alkyne groups of components A, B and C (if present) and involving the functional groups of component D (if present); wherein the hydrophilic coating optionally comprises component E which comprises one or more beneficial agents, wherein component E does not form a copolymer with components A, B, C (if present) and D (if present); and wherein the hydrophilic coating is covalently attached to the surface of the substrate.