Gemini Hydrogel Mesh Size Control for Cartilage-Like Lubricity

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Solution Overview

Problem

Hydrogels used in biomedical devices, such as contact lenses, often have high friction coefficients, which is inadequate for mimicking the low friction of biological tissues like cartilage, hindering their application as bio-tissue substitutes, and existing methods for measuring lubricity are not suitable for in-vivo conditions or for comparing the true lubricity of different systems.

Innovation Solution

A biomedical device with a surface layer of hydrogel having a targeted mesh size between 4.5 nm and 10.6 nm to achieve a lubricity equal or superior to cartilage, achieved through specific surface treatments and coating conditions, and a method for producing such devices by selecting appropriate coating materials and curing conditions to control the mesh size.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If hydrogels are used as biomedical devices, then they provide biocompatibility and tissue-like properties, but they exhibit high friction coefficients that are inadequate for mimicking biological tissues

Engineering Contradiction:
ImprovebiocompatibilityVSAvoidfriction coefficient
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by treating only the surface layer of the hydrogel contact lens with specific mesh size control (4.5-10.6 nm) to achieve low friction, while the bulk material maintains its biocompatible hydrogel properties. This localized surface modification resolves the contradiction by providing tissue-like lubricity where needed without compromising overall biocompatibility.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes the physical parameter of mesh size in the surface layer to achieve the desired friction coefficient. By controlling the mesh size to be between 4.5-10.6 nm, the surface layer achieves cartilage-like lubricity (CoF ≤ 0.02) while the bulk hydrogel maintains its biocompatible structure and properties.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If conventional lubricity measurement methods are used, then measurements can be obtained, but they are not suitable for in-vivo conditions or for comparing true lubricity of different systems

Engineering Contradiction:
Improvemeasurement capabilityVSAvoidlubricity measurement accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent creates a simplified copy of the in-vivo environment by using a hydrogel-coated substrate that mimics the corneal surface. This model system allows for controlled in-vitro measurements that accurately reflect in-vivo conditions, enabling precise comparison of lubricity across different hydrogel systems without requiring complex in-vivo testing.

Inventive Principle:
Principle #26Copying

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 approach results in a hydrogel contact lens with a friction coefficient comparable to cartilage, enhancing comfort and usability by controlling the mesh size to achieve the desired lubricity, which is not attainable with conventional methods.

Implementation Method 1

the mesh size of which is controlled to give the biomedical device a lubricity equal or superior to the lubricity reported for cartilage

Methodology Applied
Scientific EffectLubrication: Lubrication

Data Source

PatentEP3268804B1Mesh size control of lubrication in gemini hydrogels
Publication Date: 2020.11.04 UNIV OF FLORIDA RESEARCH FOUNDATION INC
  • EP3268804B1 patent drawingFigure 1
  • EP3268804B1 patent drawingFigure 2A
  • EP3268804B1 patent drawingFigure 2B~2C

AI summary

A device comprises a surface that is a hydrogel having a targeted mesh size that permits a low-speed friction coefficient near or lower that that typically reported for cartilage of 0.01 to 0.02, a transition. The device can be a contact lens to sit on the cornea where, during a blink, eyelid slides past the eye surface at about 100 mm s'1. The hydrodynamic lubrication of the hydrogel of the device separates the contact lens surface from the surfaces of the tarsal conjunctiva and marginal conjunctiva of the eyelid. Other devices that can comprise the hydrogel of a targeted mesh size are those that can contact cartilage of articulating joints.