Medical Device Coating Layer Wettability and Lubricity
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Solution Overview
Problem
Soft contact lenses with existing hydrogel materials face issues of adhesion to the cornea, bacterial proliferation, and high production costs due to lengthy and complex coating processes, which compromise antifouling properties and lubricity.
Innovation Solution
A medical device with a coating layer made of alternating acidic and basic polymer layers, formed through radical copolymerization of specific monomers, applied to a silicone hydrogel base material with a water content greater than 10%, enhancing wettability, lubricity, and antifouling properties while simplifying the production process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If LbL coating is carried out with many layers (4-20 layers) to improve hydrophilic property, then the hydrophilic property of the surface is improved, but the production process becomes longer and production cost increases
Solution Approach 1:
The patent divides the coating process into two distinct segments: (1) forming a hydrophilic polymer layer to improve wettability and lubricity, and (2) forming a zwitterionic polymer layer to provide antifouling properties. This segmentation allows each layer to be optimized for its specific function rather than requiring multiple alternating layers, thereby reducing the total number of coating steps while maintaining or improving overall performance.
Solution Approach 2:
The patent applies different polymer compositions to different regions/layers of the coating structure. The hydrophilic polymer layer provides local hydrophilic quality for wettability, while the zwitterionic polymer layer provides local antifouling quality. This local differentiation of material properties allows each layer to perform its specific function efficiently without requiring the entire multi-layer alternating structure.
2Reliability
If LbL coating with many layers is used to improve hydrophilic property, then the surface hydrophilic property is improved, but antifouling properties particularly lipid adhesion resistance are not improved
Solution Approach 1:
The patent creates a composite coating structure combining two different polymer materials with complementary properties: a hydrophilic polymer (such as polyacrylic acid or chitosan) for wettability enhancement, and a zwitterionic polymer (such as poly(sulfobetaine methacrylate) or poly(carboxybetaine)) for antifouling protection. This composite approach allows the coating to simultaneously achieve hydrophilic surface properties and resistance to lipid adhesion and bacterial proliferation that cannot be obtained with a single polymer type or alternating layer structure.
3Reliability
If alternating acidic and basic polymer layers are formed to improve hydrophilic property, then wettability is improved, but the production cost increases due to complex process
Solution Approach 1:
The patent extracts and eliminates the unnecessary alternating layer structure from the conventional LbL coating process. Instead of requiring multiple alternating acidic and basic polymer layers, the invention extracts only the essential functional components: one hydrophilic polymer layer and one zwitterionic polymer layer. This simplification reduces the number of coating steps, decreases production complexity, and lowers manufacturing costs while preserving the essential wettability improvement function.
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 solution significantly reduces adhesion to the cornea, improves bacterial resistance, and provides excellent mechanical properties, flexibility, and wearing comfort, while being produced inexpensively and efficiently.
Implementation Method 1
The layers of each material are considered to be bonded to the other layers made of a different material in a noncovalent bond manner
Implementation Method 2
it is obtained by a radical copolymerization of a monomer having one or more groups having acidity and a polymerizable group in one molecule and a monomer having one or more hydroxy groups and a radically polymerizable functional group in one molecule
Data Source
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AI summary
Provided is a medical device having excellent wettability and lubricity and reducing a risk of bacterial proliferation. The medical device of the present invention is a medical device in which a layer made of an acidic polymer and a basic polymer is formed on at least a part of a surface of a water-containing base material. At least one kind of an acidic polymer and a basic polymer forming the acidic polymer or the basic polymer is a polymer having a hydroxy group, and the polymer having a hydroxy group is obtained by radical copolymerization of an acidic monomer or a basic monomer and a monomer having a hydroxy group.