Biocompatible Polymeric Coating for Contact Lenses
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Solution Overview
Problem
Current biocompatible polymer coatings for medical devices, such as contact lenses, face challenges in achieving high levels of phosphorylcholine incorporation while maintaining compatibility with silicone monomers, leading to inadequate protein prevention and surface denaturation.
Innovation Solution
A biocompatible polymeric coating is developed by reacting methacrylic acid with hydroxyethyl methacrylate, polyethylene glycol monomethacrylate, and methacryloyloxyethyl phosphorylcholine, using a coupling agent like polyaziridine or carbodiimide to form a stable, water-compatible coating that is covalently bonded to the substrate, with high phosphorylcholine content preventing protein absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If high levels of phosphorylcholine are incorporated into the polymer coating, then protein prevention capability is improved, but compatibility with silicone monomers deteriorates
Solution Approach 1:
The patent uses composite polymer materials combining multiple monomers (silicone monomers, HEMA, and phosphorylcholine-containing monomers) to create a coating that achieves high phosphorylcholine content (30-80 mole %) while maintaining structural stability and compatibility. The composite nature allows the phosphorylcholine units to prevent protein deposition while the HEMA and silicone components provide structural framework and monomer compatibility.
2Object-affected harmful factors
If phosphorylcholine content is increased to prevent protein absorption, then surface denaturation resistance is improved, but polymer insolubility in nonpolar solvents worsens
Solution Approach 1:
The patent changes the chemical composition parameters by incorporating hydrophilic monomers (HEMA and phosphorylcholine-containing monomers) alongside silicone monomers. This parameter change increases phosphorylcholine content to achieve protein resistance while the specific balance of hydrophilic and hydrophobic components controls the polymer's solubility characteristics, making it insoluble in nonpolar solvents while maintaining functional performance.
3Reliability
If coupling agents like polyaziridine or carbodiimide are used to covalently bond the coating to substrate, then coating stability is improved, but manufacturing complexity increases
Solution Approach 1:
The patent uses coupling agents (polyaziridine or carbodiimide) as intermediary substances that facilitate covalent bonding between the polymer coating and the substrate surface. These coupling agents act as mediators that react with both the coating polymer and the substrate, creating stable covalent bonds without requiring complex manufacturing equipment or processes, thus achieving reliable coating adhesion with relatively simple manufacturing.
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 coating effectively prevents protein deposition and denaturation, offering improved wetting characteristics and mechanical integrity, with high phosphorylcholine content maintaining insolubility in nonpolar solvents and enhancing oxygen permeability.
Implementation Method 1
contacting and reacting methacrylic acid (MAA) and at least one of hydroxyethyl methacrylate (HEMA), polyethylene glycol monomethacrylate (PEGMA), and methacryloyloxyethyl phosphorylcholine (MPC) to form a polymer solution
Implementation Method 2
mixing and reacting the polymer solution with the coupling agent solution to form the coating solution... the coupling agent within the coupling agent solution may be one or more of polyaziridine, azetidinium functionalized water soluble polymers, a water soluble carbodiimide, a diisocyanate or an isocyanate polymer
Implementation Method 3
high phosphorylcholine content preventing protein absorption
Implementation Method 4
Phosphorylcholine is a zwitterionic head group based on phosphatidylcholine in mammalian cell membranes
Implementation Method 5
enhancing oxygen permeability
Data Source
AI summary
A method of preparing a biocompatible polymeric coating includes preparing an aqueous polymer solution by contacting and reacting methacrylic acid and at least one methacrylate or phosphorylcholine. The methacrylate or phosphorylcholine may include hydroxyethyl methacrylate, polyethylene glycol monomethacrylate, or methacryloyloxyethyl phosphorylcholine. An aqueous coupling agent solution is prepared and is either applied to the substrate surface or is mixed with the polymer solution to form a coating solution. If the coupling agent solution was first applied to the substrate surface, the polymer solution is then applied to the primed substrate surface. Alternatively if a coating solution was created, the coating solution is applied to the substrate surface. In either event, the polymer solution and coupling agent solution react with the substrate to form the biocompatible polymeric coating on the substrate surface.