Luminal Prostheses Coating Adhesion via Surface Modification

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Solution Overview

Problem

Luminal prostheses, such as stents, face challenges with polymer coatings that crack or smear during deformation and delivery due to strain, affecting their efficacy and biocompatibility in vascular applications.

Innovation Solution

The development of modified surface regions on stents with coatings that soften in physiological environments, using polymers like poly(alkene carbonate) and copolymers of poly(lactide) and trimethylene carbonate, which provide enhanced adherence and minimize cracking, along with specific solvent selection and surface texturing to promote adhesion and reduce residual solvents.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If polymer coatings are applied to luminal prostheses for drug delivery and biocompatibility, then therapeutic efficacy and biocompatibility are improved, but the coatings are prone to cracking and smearing during deformation and delivery

Engineering Contradiction:

Improvecoating integrityVSAvoidcracking and smearing

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent modifies the surface energy parameters of the prosthesis surface through plasma treatment, corona discharge, or chemical etching to optimize coating adhesion. These parameter changes in surface roughness and surface energy prevent coating cracking and smearing during deformation while maintaining drug delivery efficacy

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses composite polymer coatings combining multiple materials with complementary properties - such as adhesion-promoting layers coupled with drug-eluting matrices - to achieve both mechanical integrity during delivery and therapeutic function. The composite structure prevents cracking while enabling controlled drug release

Inventive Principle:

Principle #40Composite materials

2Ease of operation

If the prosthesis is crimped and expanded during delivery and deployment, then the prosthesis can be delivered through catheters and deployed in the target vessel, but the coating undergoes deformation strain that causes cracking and smearing

Engineering Contradiction:

ImprovedeliverabilityVSAvoidcoating uniformity

Core Design Contradiction:

Ease of operationVSManufacturing precision

Solution Approach 1:

The patent applies preliminary surface modifications and coating optimizations before the crimping and expansion process. Adhesion promoters are applied in advance, and coating thicknesses are pre-engineered to accommodate expected deformation strains without cracking, ensuring coating uniformity is maintained throughout delivery and deployment

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent employs thin-film coating technologies that create flexible, conformal layers capable of withstanding crimping and expansion deformations. These thin films maintain coating uniformity through the mechanical stresses of delivery while enabling complete drug release upon expansion

Inventive Principle:

Principle #30Flexible shells and thin films

3Ease of manufacture

If conventional coating methods are used without surface modification, then the fabrication process is simpler, but the coating adherence is insufficient and cracking occurs during deformation

Engineering Contradiction:

Improvefabrication simplicityVSAvoidcoating adhesion

Core Design Contradiction:

Ease of manufactureVSStrength

Solution Approach 1:

The patent replaces mechanical adhesion alone with chemically-enhanced adhesion through surface plasma treatment or chemical etching. These treatments create chemical bonds between the coating and substrate, dramatically improving coating adhesion strength without significantly complicating the fabrication process

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent modifies surface energy and surface roughness parameters through relatively simple treatments like corona discharge or acid etching. These parameter changes enhance coating adhesion strength by creating a more favorable surface for chemical bonding, while maintaining fabrication simplicity through established, scalable processes

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 modified stents with enhanced polymer coatings exhibit improved resistance to cracking and smearing during crimping and expansion, maintaining biocompatibility and effective drug release, comparable to existing systems like the Rapamycin eluting Cypher™ stent, with controlled agent release profiles.

Implementation Method 1

a coating comprising a material which softens in a physiologic environment and interacts with the modified surface region to provide an adherence of the coating to the surface greater than an adherence in the absence of the surface modification

Methodology Applied

Scientific EffectPhase change: Phase Change

Data Source

PatentUS9937280B2Luminal prostheses and methods for coating thereof

Publication Date: 2018.04.10 ELIXIR MEDICAL CORP

AI summary

Luminal prostheses comprise scaffolds having coatings adhered to at least a portion of their outer surfaces. The surfaces are modified to enhance binding of the coatings. For example, the surfaces may be microblasted, laser treated, chemically etched, exposed to plasma, or exposed to a corona discharge, allowing a polymeric coating to adhere to the scaffold more tightly than in the absence of the surface modification. The coatings can be used to deliver therapeutic or other agents dispersed therein.