Hydrophilic Copolymer Coating for Catheter Sliding Control
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Solution Overview
Problem
Medical devices, such as catheters, face challenges in maintaining high initial sliding property to navigate through biological tissues with minimal damage and then reducing sliding property post-target lesion to prevent misalignment during procedures.
Innovation Solution
A hydrophilic copolymer comprising more than 50% of a polymerizable monomer with a lower critical solution temperature (LCST), a sulfonic acid group-containing monomer, and a photoreactive monomer, forming a coating layer that enhances initial sliding property and maintains it after multiple frictions, while reducing sliding property upon heating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a coating layer containing temperature-sensitive polymer and reactive polymer is used, then sliding property changes after reaching target site, but initial sliding property is low in steady environment (25°C) and sliding property greatly fluctuates when rubbed multiple times
Solution Approach 1:
The patent applies composite materials by combining three specific polymer components: (A) a temperature-sensitive polymer with LCST of 37-42°C, (B) a polymer with sulfonic acid groups or sulfate groups providing hydrophilicity and lubrication, and (C) a photoreactive polymer for light-triggered crosslinking. This composite coating layer achieves both high initial sliding property and reliable sliding property change after target site arrival, resolving the contradiction between adaptability and reliability.
Solution Approach 2:
The patent utilizes parameter changes by selecting polymers with specific thermal and photochemical properties. The temperature-sensitive polymer (A) changes its conformation and hydrophilicity in response to temperature increase after reaching the target site, while the photoreactive polymer (C) undergoes crosslinking upon UV irradiation to permanently reduce sliding property. These parameter changes enable the coating to provide high initial sliding property followed by controlled reduction, resolving the reliability issue of sliding property fluctuation.
2Object-affected harmful factors
If high sliding property is maintained to reach target lesion, then tissue damage is reduced, but sliding property must be reduced after reaching target to prevent position shift
Solution Approach 1:
The patent applies dynamics by designing a coating layer that dynamically changes its sliding property in response to environmental changes. The temperature-sensitive polymer (A) responds to body temperature increase by changing its hydrophilic-hydrophobic balance, and the photoreactive polymer (C) responds to UV irradiation by crosslinking. This dynamic response allows the coating to provide high sliding property during insertion to minimize tissue damage, then reduce sliding property at the target site to ensure position stability, thereby resolving the contradiction between ease of operation and harmful factors.
Solution Approach 2:
The patent utilizes phase transitions by employing a temperature-sensitive polymer (A) that undergoes a conformational phase transition at its LCST (37-42°C). Below the LCST, the polymer is hydrophilic and provides high sliding property; above the LCST, it becomes hydrophobic and reduces sliding property. This phase transition mechanism enables automatic adjustment of sliding property based on temperature, resolving the contradiction between minimizing tissue damage during insertion and ensuring position stability at the target lesion.
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 hydrophilic copolymer coating layer ensures high sliding property for navigating to the target lesion with minimal tissue damage and reduces sliding resistance post-procedure, preventing misalignment by controlling temperature-dependent sliding properties.
Implementation Method 1
a structural unit derived from a polymerizable monomer (A) from which a homopolymer having a lower critical solution temperature (LCST) is formed
Implementation Method 2
a structural unit derived from a polymerizable monomer (C) having a photoreactive group
Data Source
AI summary
Disclosed is a hydrophilic copolymer including more than 50% by mol of a structural unit derived from a polymerizable monomer (A) from which a homopolymer having a lower critical solution temperature (LCST) is formed, a structural unit derived from a polymerizable monomer (B) having at least one group selected from the group consisting of a sulfonic acid group (−SO3H), a sulfate group (−OSO3H), a sulfurous acid group (−OSO2H), and a group of salts thereof, and a structural unit derived from a polymerizable monomer (C) having a photoreactive group. Also disclosed is a medical device including the hydrophilic copolymer. The medical device exhibits high sliding property until it reaches a target lesion, and low sliding property after reaching the target lesion. Methods of making and using the hydrophilic copolymer and medical device are also described.