Bile Duct Stent Sludge Resistance via PMEA Coating

Solution Overview

Problem

Stents placed in bile ducts are prone to occlusion due to denaturation of biological components like proteins and bile acids, leading to the formation of sludge that clogs the stent lumen, increasing the frequency of replacement and patient load.

Innovation Solution

A stent with a sludge-resistant resin layer formed by polymerizing 2-methoxyethyl acrylate is applied to the inner surface, preventing denaturation of biological components and reducing deposition, thereby maintaining stent lumen patency over extended periods.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a covered stent or tube stent is used to prevent tissue invasion, then the suppression of body tissue invasion is improved, but the stent lumen occlusion by sludge increases

Engineering Contradiction:

Improvebody tissue invasionVSAvoidstent lumen patency

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent applies different surface properties to different regions of the stent. The outer surface maintains a covered structure to prevent tissue invasion, while the inner surface is treated with a hydrophilic coating to prevent sludge accumulation. This local differentiation resolves the contradiction by optimizing each surface for its specific function.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The stent combines multiple materials with different properties: the base stent structure (metal or polymer), the outer cover material (for tissue protection), and the inner hydrophilic coating material (for sludge prevention). This composite approach allows simultaneous achievement of tissue invasion prevention and lumen patency maintenance.

Inventive Principle:

Principle #40Composite materials

2Object-affected harmful factors

If a covered stent is used to suppress tissue invasion, then the protection against tissue invasion is improved, but the frequency of stent replacement increases due to lumen occlusion

Engineering Contradiction:

Improvetissue invasionVSAvoidstent service life

Core Design Contradiction:

Object-affected harmful factorsVSDuration of action of stationary object

Solution Approach 1:

The patent applies different surface properties to different regions of the stent. The outer surface maintains a covered structure to prevent tissue invasion, while the inner surface is treated with a hydrophilic coating to prevent sludge accumulation. This local differentiation resolves the contradiction by optimizing each surface for its specific function.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The stent combines multiple materials with different properties: the base stent structure (metal or polymer), the outer cover material (for tissue protection), and the inner hydrophilic coating material (for sludge prevention). This composite approach allows simultaneous achievement of tissue invasion prevention and lumen patency maintenance.

Inventive Principle:

Principle #40Composite materials

3Ease of manufacture

If a standard stent surface is used, then the manufacturing simplicity is maintained, but the denaturation of biological components on the stent surface occurs

Engineering Contradiction:

Improvestent manufacturingVSAvoidbiological component denaturation

Core Design Contradiction:

Ease of manufactureVSObject-generated harmful factors

Solution Approach 1:

The hydrophilic coating is applied to the stent inner surface during the manufacturing process, before the stent is implanted. This preliminary action ensures that the surface is pre-treated to prevent biological component denaturation, eliminating the need for post-implantation interventions.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent changes the surface energy parameters of the stent inner surface by applying a hydrophilic coating. This parameter change (increasing hydrophilicity) prevents protein denaturation and sludge formation, while the coating process is designed to be compatible with existing manufacturing methods.

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 sludge-resistant resin layer effectively prevents occlusion of the stent lumen, reducing the need for frequent replacements and ensuring stent functionality over time by inhibiting the deposition of denatured biological materials.

Implementation Method 1

a sludge-resistant resin layer covering the inner peripheral surface of the stent and containing a polymer obtained through polymerization of 2-methoxyethyl acrylate

Methodology Applied

Scientific EffectPolymerization: Photopolymerisation

Implementation Method 2

PMEA is used upon being coated on the surface of a medical instrument or the like coming into contact with blood

Methodology Applied

Scientific EffectAnti-adhesion:

Data Source

PatentUS10080640B2Stent to be placed in bile duct

Publication Date: 2018.09.25 PIOLAX MEDICAL DEVICES

AI summary

Provided are a stent to be placed in the bile duct and a process for producing the stent, the stent hollow being less apt to be blocked even when the stent is placed in the bile duct for a long period. The inner peripheral surface of the stent is coated with a resin layer with resistance to sludge formation that includes a polymer obtained by polymerizing 2-methoxyethyl acrylate. This stent is produced by applying a coating fluid that contains 0.1-0.5 mass % polymer obtained by polymerizing 2-methoxyethyl acrylate, to the inner peripheral surface of a stent.