Isocyanate Prepolymer Tissue Adhesive Biodegradability
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Solution Overview
Problem
Current tissue adhesives face challenges such as rapid curing, brittleness, poor biodegradability, and limited biocompatibility, making them unsuitable for various surgical applications, particularly in plastic surgery where flexibility and long-term adhesion are required.
Innovation Solution
A method for producing an isocyanate-functional prepolymer by reacting an H-functional starter compound with alkylene oxide and a co-monomer, followed by incorporation of an amino-functional aspartic acid ester, resulting in a tissue adhesive with adjustable curing speed, high adhesion, and biodegradability suitable for physiological conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If cyanoacrylate-based adhesives are used, then rapid curing is achieved, but brittleness and poor biodegradability occur
Solution Approach 1:
The patent uses a composite material system combining a polyol component with ester groups (for biodegradability) and an isocyanate component (for rapid curing), creating a polyurea polymer that integrates multiple desirable properties: fast curing, flexibility, and biodegradability
Solution Approach 2:
The patent modifies the chemical structure by incorporating ester groups into the polyol component, which changes the degradation parameters of the adhesive to enable biodegradation while maintaining curing speed through the isocyanate component
2Strength
If hydrophilic polyurethane systems are used, then adhesion strength is improved, but swelling in water reduces durability
Solution Approach 1:
The patent introduces ester groups at specific locations within the polymer structure (in the polyol component), creating localized hydrolyzable sites that enable controlled degradation without compromising overall structural stability or adhesion strength
3Reliability
If biological adhesives are used, then biocompatibility is improved, but rapid degradation limits application scope
Solution Approach 1:
The patent creates a dynamic system where the adhesive maintains stability during the healing period through the isocyanate-polyol reaction structure, then progressively degrades via ester hydrolysis, adapting its properties over time to match the wound healing process
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 tissue adhesive system exhibits a curing time of less than 5 minutes, strong adhesion to human or animal tissue, and degrades within the wound healing period, meeting requirements for histotoxicity, thrombogenicity, and allergenic potential, while allowing for flexible application and effective wound closure.
Implementation Method 1
Two-component adhesive systems based on polyurea are known from EP 2 145 634 A1. These are available by reacting isocyanate-functional prepolymers based on aliphatic isocyanates with special secondary diamines structurally derived from amino acids.
Implementation Method 2
The ester groups are produced by statistical copolymerization of alkylene oxide compounds and lactides, glycolides and/or cyclic dicarboxylic acid anhydrides. The tissue adhesive systems are designed to biodegrade within a period of up to 6 months.
Implementation Method 3
The isocyanate-functional prepolymer contains building blocks originating from lactides, glycolides and/or cyclic dicarboxylic acid anhydrides, which are incorporated into the polymer chain of the precursor bearing hydroxyl groups by statistical copolymerization.
Data Source
AI summary
The present invention relates to a process for producing a tissue adhesive for closing or joining cell tissues, comprising the steps of producing an isocyanate-functional prepolymer as component A) by a) reacting an H-functional starter compound having at least one Zerewitinoff-active H atom with an alkylene oxide compound and a co-monomer to form a hydroxyl-bearing precursor, wherein the co-monomer is selected from the group comprising lactides, glycolides, cyclic dicarboxylic anhydrides and combinations thereof, and wherein the co-monomer is incorporated into the polymer chain(s) of the hydroxyl-bearing precursor by statistical copolymerization, and b) reacting the hydroxyl-bearing precursor from step a) with a polyfunctional isocyanate to form the isocyanate-functional prepolymer A).Providing a component B) in the form of an amino-functional aspartic acid ester of general formula (I) wherein X is an n-valent organic residue, R1, R2 are identical or different organic residues that do not contain any zerewitinoff-active hydrogen atoms, n is an integer ≥ 2, in particular 2 or 3, and/or a component C) in the form of a reaction product of the isocyanate-functional prepolymer A) with amino-functional aspartic acid esters B). The invention further relates to a tissue adhesive obtainable by this process, a tissue adhesive system containing such a tissue adhesive, and a dispensing system with at least two chambers and such a tissue adhesive system.