Crosslinkable Polyelectrolyte Coatings for Medical Devices
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Solution Overview
Problem
Current methods for modifying the surface properties of medical devices, such as contact lenses, face challenges including high costs and inefficiencies in plasma treatment and delamination issues with existing polyelectrolyte coatings, particularly in achieving durability against autoclaving and rubbing.
Innovation Solution
A method involving the application of crosslinkable polycationic and polyanionic materials, derived from alpha-halogeno epoxides or alpha-cyanato epoxides and polyamines, which are deposited in layers and cross-linked to form a robust coating, suitable for medical devices like contact lenses, enhancing durability and hydrophilicity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If plasma treatment is used to modify surface properties, then hydrophilicity is improved, but equipment cost and processing time increase
Solution Approach 1:
The patent replaces the plasma treatment process (physical/chemical field-based method) with a layer-by-layer deposition of polyelectrolyte coatings (chemical method). This substitution eliminates the need for expensive plasma equipment while achieving the desired hydrophilic surface modification through sequential application of charged polymer layers.
Solution Approach 2:
The patent modifies surface properties by changing the chemical composition parameters through polyelectrolyte coating deposition. By controlling the charge density, molecular weight, and concentration of polycationic and polyanionic materials, the surface hydrophilicity is adjusted without requiring plasma treatment equipment.
2Manufacturing precision
If sequential dipping is used for layer-by-layer coating, then coating uniformity is improved, but processing time increases
Solution Approach 1:
The patent combines multiple layer-by-layer coating steps into a single dip process. By incorporating multiple polyelectrolyte layers into one coating solution or applying multiple layers simultaneously during a single immersion, the method maintains coating uniformity while dramatically reducing the time required compared to sequential dipping of each layer individually.
3Stability of the object's composition
If multiple polyelectrolyte bilayers are deposited, then surface hydrophilicity is improved, but delamination occurs
Solution Approach 1:
The patent uses composite polyelectrolyte coatings combining polycationic and polyanionic materials in alternating layers. This composite structure creates strong electrostatic interactions between adjacent layers, forming a robust multi-layer coating that resists delamination during autoclaving and rubbing while maintaining high surface hydrophilicity.
Solution Approach 2:
The patent employs cross-linking of the polyelectrolyte layers to create a three-dimensional network structure. This cross-linked configuration provides mechanical strength and resistance to delamination, while the layered architecture maintains the hydrophilic properties needed for surface performance.
4Ease of manufacture
If conventional coating methods are used, then manufacturing simplicity is maintained, but coating durability against autoclaving and rubbing is insufficient
Solution Approach 1:
The patent employs self-assembly of polyelectrolyte layers through electrostatic interactions. The polycationic and polyanionic materials automatically arrange themselves into stable bilayers during the coating process without requiring complex external control systems, maintaining manufacturing simplicity while achieving durable, autoclave-resistant coatings through the inherent properties of the 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 method provides a durable polyelectrolyte coating that is resistant to autoclaving and rubbing, improving the hydrophilicity and stability of medical devices like contact lenses, reducing delamination and production costs.
Implementation Method 1
the polycationic material is a reaction product of an alpha-halogeno epoxide or an alpha-cyanato epoxide and a polyamine
Implementation Method 2
applying one or more layers of a crosslinkable polycationic material... applying one or more layers of a polyanionic material
Implementation Method 3
cross-linking the layers of polyelectrolytes formed by steps (b) and (c)
Data Source
AI summary
A method for making an article comprising a core material and a coating thereon, the method comprising the steps of:(a) providing the core material;(b) applying one or more layers of a crosslinkable polycationic material, wherein the polycationic material is a reaction product of:(i) an epoxide of formula (I)wherein X equals bromo, chloro, iodo, or cyano, and R1, R2, R3, R4, independently of one another, are selected from the group consisting of hydrogen, linear or branched C1-C6-alkyl, and linear or branched C1-C6-alkyl which is substituted with halogen, and(ii) a polymer having repeating units comprising one or more secondary or tertiary amine group(s);(c) applying one or more layers of a polyanionic material; and(d) cross-linking the layers of polyelectrolytes formed by steps (b) and (c).The articles obtainable by the method of the invention have desirable characteristics regarding adherence to the core material, durability, hydrophilicity, and wettability and are thus useful for the manufacture of medical articles such as ophthalmic devices.