RAFT Copolymer Contact Lens Surface Wettability

Solution Overview

Problem

Current contact lenses, particularly those made of soft hydrogel materials, face challenges in balancing oxygen permeability, wettability, and biocompatibility, leading to issues such as rapid drying and protein/lipid deposition, which affect comfort and clarity during extended wear.

Innovation Solution

The development of ophthalmic devices using random copolymers with hydrophilic and hydrophobic units, incorporating a reversible addition-fragmentation chain transfer (RAFT) agent, which enhances surface hydrophilicity and prevents protein/lipid adsorption, thereby improving comfort and clarity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If contact lenses are made with hydrophobic materials to maintain material strength and stability, then structural integrity is improved, but wettability and comfort deteriorate

Engineering Contradiction:

Improvematerial strengthVSAvoidwettability

Core Design Contradiction:

StrengthVSEase of operation

Solution Approach 1:

The patent applies local quality by creating a contact lens with distinct hydrophobic and hydrophilic regions. The bulk material remains hydrophobic for structural integrity, while the surface is modified to be hydrophilic for improved wettability. This is achieved through surface treatment or coating techniques that selectively alter the surface properties without changing the bulk material composition.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent employs composite materials by combining hydrophobic base materials with hydrophilic surface layers or coatings. This multi-layer composite structure allows the lens to simultaneously exhibit the mechanical strength of hydrophobic materials and the wettability of hydrophilic materials, resolving the contradiction between structural integrity and surface comfort.

Inventive Principle:

Principle #40Composite materials

2Ease of operation

If contact lenses are made with hydrophilic materials to improve wettability, then comfort is improved, but oxygen permeability deteriorates

Engineering Contradiction:

ImprovewettabilityVSAvoidoxygen permeability

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent applies local quality by creating a contact lens with distinct hydrophobic and hydrophilic regions. The bulk material remains hydrophobic for structural integrity, while the surface is modified to be hydrophilic for improved wettability. This is achieved through surface treatment or coating techniques that selectively alter the surface properties without changing the bulk material composition.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent employs composite materials by combining hydrophobic base materials with hydrophilic surface layers or coatings. This multi-layer composite structure allows the lens to simultaneously exhibit the mechanical strength of hydrophobic materials and the wettability of hydrophilic materials, resolving the contradiction between structural integrity and surface comfort.

Inventive Principle:

Principle #40Composite materials

3Duration of action of moving object

If contact lenses are designed for extended wear to improve convenience, then duration of action is improved, but susceptibility to protein and lipid deposition increases

Engineering Contradiction:

Improvewear durationVSAvoidprotein and lipid deposition

Core Design Contradiction:

Duration of action of moving objectVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary anti-action by pre-treating the lens surface with hydrophilic coatings or plasma treatment before the lens comes into contact with tear fluids. This preliminary modification creates a surface that is inherently resistant to protein and lipid adsorption, preventing the accumulation of deposits that would otherwise occur during extended wear.

Inventive Principle:

Principle #9Preliminary anti-action

Solution Approach 2:

The patent employs composite materials by combining hydrophobic base materials with hydrophilic surface layers or coatings. This multi-layer composite structure allows the lens to simultaneously exhibit the mechanical strength of hydrophobic materials and the wettability of hydrophilic materials, resolving the contradiction between structural integrity and surface comfort.

Inventive Principle:

Principle #40Composite 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 RAFT-based random copolymers create a lubricious surface that reduces protein and lipid absorption, maintaining lens clarity and comfort by enhancing hydrophilicity and preventing rapid drying.

Implementation Method 1

one or more random copolymers having at least one thio carbonyl thio fragment of a reversible addition fragmentation chain transfer ('RAFT') agent

Methodology Applied

Scientific EffectReversible addition-fragmentation chain transfer (RAFT):

Implementation Method 2

Hydrogels are a cross-linked polymeric system that absorb and retain water, typically 10 to 80 percent by weight

Methodology Applied

Scientific EffectHydrophilicity: Hydrophile

Data Source

PatentEP2443486B1Biomedical devices

Publication Date: 2017.03.01 BAUSCH & LOMB INC

AI summary

Biomedical devices such as contact lenses formed from a polymerization product of a mixture comprising one or more random copolymers comprising hydrophilic units and hydrophobic units, wherein the one or more random copolymers have at least one thio carbonyl thio fragment of a reversible addition fragmentation chain transfer ("RAFT") agent are disclosed.