Thiol-Ene Primer for Wet Bone Adhesion

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Solution Overview

Problem

Current adhesive systems for bone fractures face challenges in wet environments due to poor adhesion and biocompatibility issues, limiting their expansion in clinical applications beyond traditional metal fixation methods.

Innovation Solution

A thiol-ene coupling polymerization-based primer composition that enhances adhesion to wet bone surfaces, using a combination of thiol-containing compounds, phosphonic acid groups, and alkynes to form a stable crosslinked network, reducing monomer leakage and curing shrinkage stress, and incorporating ceramic fillers like calcium phosphate for improved mechanical strength.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If acrylate-based adhesive systems are used to achieve adhesion to bone surfaces, then adhesion strength is improved, but biocompatibility deteriorates due to cytotoxic leakage of unreacted monomers

Engineering Contradiction:
Improveadhesion strengthVSAvoidcytotoxicity
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The patent changes the chemical parameters of the adhesive system by replacing acrylate monomers with thiol-ene coupling polymerization systems. This fundamental chemical parameter change eliminates the cytotoxicity issue while maintaining adhesion strength, as thiol-ene systems do not exhibit the same monomer leakage problems as acrylate systems.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs a composite primer composition containing phosphonic acid compounds, carboxylic acid compounds, and thiol compounds. This composite approach combines multiple functional components to achieve both strong adhesion to bone (through phosphonic and carboxylic acid groups binding to calcium) and biocompatibility (through the thiol-ene polymerization system that minimizes toxic byproducts).

Inventive Principle:
Principle #40Composite materials

2Strength

If traditional metal fixation methods are used for bone fractures, then mechanical strength is improved, but biocompatibility and patient comfort deteriorate compared to adhesive systems

Engineering Contradiction:
Improvemechanical strengthVSAvoidbiocompatibility issues
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the mechanical fixation system (screws, plates, and metal implants) with a chemical adhesive bonding system. The thiol-ene primer creates strong chemical bonds to the bone surface, substituting mechanical interlocking with chemical adhesion, thereby eliminating the need for foreign metal objects in the body while maintaining structural integrity.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the fundamental bonding mechanism from mechanical (physical interlocking with metal implants) to chemical (covalent and ionic bonding through thiol-ene polymerization and phosphonic acid-calcium interactions). This parameter change in bonding mechanism achieves both strength and improved biocompatibility.

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If adhesive systems are applied to wet bone surfaces, then application ease is improved, but adhesion strength deteriorates due to poor adhesion in wet environments

Engineering Contradiction:
Improveapplication easeVSAvoidadhesion strength
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The patent uses phosphonic acid compounds and carboxylic acid compounds as intermediary agents that bridge the wet bone surface and the hydrophobic thiol-ene adhesive matrix. These acidic compounds can interact with both the aqueous environment (forming ionic bonds with calcium on wet bone) and the organic adhesive phase, enabling effective adhesion despite the presence of moisture.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the chemical parameters of the primer to include amphiphilic characteristics - components that can interact with both aqueous (wet) environments and organic adhesive phases. The phosphonic and carboxylic acid groups provide hydrophilic interaction with wet bone, while the thiol-ene components provide hydrophobic adhesive bonding, creating a bridge across the wet interface.

Inventive Principle:
Principle #35Parameter changes

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 primer composition achieves high shear bond strength and biocompatibility, enabling effective fixation of bone fractures with reduced toxicity and improved mechanical properties compared to traditional acrylate-based systems, and can be used in both bone and dental applications.

Implementation Method 1

the use of acrylate monomers with acidic adhesion-enhancing groups of phosphoric, phosphonic or carboxylic acid have enabled self-etch adhesive systems. The acidic monomers dissolve hydroxyapatite and create ionic bonds to calcium ions forming precipitates with very low solubility that integrate within the hydroxyapatite surface.

Methodology Applied
Scientific EffectIonic bonding: Coulomb's Law

Implementation Method 2

The acidic monomers dissolve hydroxyapatite and create ionic bonds to calcium ions forming precipitates with very low solubility that integrate within the hydroxyapatite surface.

Methodology Applied
Scientific EffectPrecipitation: Precipitation

Implementation Method 3

A thiol-ene coupling polymerization-based primer composition that enhances adhesion to wet bone surfaces, using a combination of thiol-containing compounds, phosphonic acid groups, and alkynes to form a stable crosslinked network

Methodology Applied
Scientific EffectPhotopolymerization: Photopolymerisation

Data Source

PatentEP3700590B1A composition comprising thiol, alkene and phosphonic acid containing compounds for use as a primer for adhesion improvement
Publication Date: 2023.07.12 BIOMEDICAL BONDING AB
  • EP3700590B1 patent drawingFigure 1a~1e
  • EP3700590B1 patent drawingFigure 2a~2f
  • EP3700590B1 patent drawingFigure 3a~3f

AI summary

The present invention relates to a primer composition that may be applied to tissue in order to increase bond strength between the tissue and a patch, filler or a supporting material. The primer comprises a dithiol component and an allyl containing component together with a photo initiator.