Natural Polymer IOL Cartridge Coating for Saline-Activated Lens Delivery
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Solution Overview
Problem
Existing intraocular lens (IOL) cartridge coatings face issues with friction, lubrication, and stability, leading to implantation failures, deformations, and optical property damage, while current solutions either require viscoelastic gels or non-flexible, hard coatings that complicate surgeries and have health risks.
Innovation Solution
A biocompatible, biodegradable coating using amine and carboxylic acid functionalized natural polymers (chitosan and hyaluronic acid) crosslinked with EDC, applied via plasma treatment and centrifugal coating, which can be activated with saline solution for easy lens delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If polyacrylic acid-co-styrene polymer is used for IOL coating, then surface adhesion is improved, but cytotoxicity increases and biocompatibility deteriorates
Solution Approach 1:
The patent changes the chemical composition parameters of the coating polymer from polyacrylic acid-co-styrene to a specific copolymer of acrylic acid and N-vinylpyrrolidone with controlled feed ratios (0.2-2.0:1), molecular weight (5000-50000), and crosslinking degree (1-50%). These parameter adjustments maintain surface adhesion while eliminating cytotoxicity and improving biocompatibility.
Solution Approach 2:
The patent creates a composite coating system combining the acrylic acid-N-vinylpyrrolidone copolymer with crosslinking agents (glycerol, pentaerythritol, or trimethylolpropane) in specific ratios. This composite structure provides both adhesion strength and biocompatibility that neither component achieves alone.
2Ease of manufacture
If conventional coating methods are used, then production simplicity is maintained, but coating uniformity and quality consistency deteriorate
Solution Approach 1:
The patent performs preliminary actions by pre-silanizing the IOL surface with (3-trimethoxysilyl)propyl methoxysilane before coating application. This pre-treatment creates optimal surface conditions that ensure uniform coating deposition and consistent quality, while the subsequent coating process remains simple and straightforward.
3Strength
If coating provides strong adhesion, then lens stability is improved, but protein adsorption increases causing posterior capsule opacification
Solution Approach 1:
The patent changes the surface chemical properties by using a copolymer with specific acrylic acid to N-vinylpyrrolidone ratios (0.2-2.0:1) and controlled crosslinking (1-50%). This creates a surface that maintains adhesion strength while presenting a protein-resistant chemistry that reduces protein adsorption and prevents posterior capsule opacification.
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 facilitates smooth lens implantation without deformation, reduces surgical time, and eliminates health risks, while being compatible with both hydrophobic and hydrophilic lenses, and cost-effective by using saline solution instead of viscoelastic gels.
Implementation Method 1
the silane coupling agent is allowed to self-assemble on the surface of the IOL
Implementation Method 2
a copolymer of acrylic acid and N-vinylpyrrolidone... is deposited on the surface of the intraocular lens
Data Source
Figure 1
AI summary
The present invention relates to biocompatible natural polymer-based coatings which are used as the inner coating material for the cartridge of intraocular lenses (IOL) and facilitate the implantation of lenses. The objective of the present invention is to provide a biocompatible, biodegradable coating material which enables to easily slide the lens without being damaged during implantation and which can easily be activated with a saline solution.