Phosphate Functionalized PEU Bone Adhesive

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Solution Overview

Problem

Current bone adhesives, such as poly(methyl methacrylate) bone cement and synthetic glues, face issues like lack of adhesion, heat generation, and poor strength, and existing alternatives lack degradable and high-strength bonding properties necessary for effective bone surgeries.

Innovation Solution

Development of a phosphate functionalized amino acid-based poly(ester urea) adhesive that mimics the properties of caddisfly adhesive silk, using a PEU polymer backbone with phosphorylated serine and valine molecules crosslinked with divalent metal salts for enhanced bonding strength and degradability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If poly(methyl methacrylate) bone cement is used, then bonding strength is achieved, but heat generation and lack of adhesion occur

Engineering Contradiction:
Improvebonding strengthVSAvoidheat generation
Core Design Contradiction:
StrengthVSObject-generated harmful factors

Solution Approach 1:

The patent changes the chemical composition parameters by using phosphate functionalized PEU polymers with specific amino acid sequences instead of PMMA, and controls the degradation rate and bonding strength through polymer structure modification while avoiding heat generation

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention creates a composite adhesive system combining phosphate functionalized PEU polymer with divalent metal ions (Ca2+, Mg2+, Sr2+, Ba2+, Zn2+) to achieve both strong bonding and degradability, merging the advantages of polymer flexibility and metal ion crosslinking

Inventive Principle:
Principle #40Composite materials

2Reliability

If degradable bone adhesives are used, then biocompatibility is improved, but bonding strength decreases

Engineering Contradiction:
ImprovebiocompatibilityVSAvoidbonding strength
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent optimizes the polymer structure by incorporating specific amino acid sequences (SX)4 motifs with phosphorylated serine and controlling the molecular weight and crosslinking density to achieve both high bonding strength (439±203 KPa) and degradability into non-toxic metabolic components

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The phosphate groups act as intermediaries that bridge the polymer and bone surface, forming strong coordinate bonds with calcium ions in the bone matrix while the polymer backbone provides structural integrity and controlled degradation

Inventive Principle:
Principle #24Intermediary (Mediator)

3Strength

If phosphate functionalized PEU adhesive is used, then adhesion strength and degradability are achieved, but manufacturing complexity increases

Engineering Contradiction:
Improveadhesion strengthVSAvoidmanufacturing complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent divides the adhesive system into two separate components: the phosphate functionalized PEU polymer and the divalent metal ion crosslinker, allowing independent synthesis and optimization of each component while simplifying the overall manufacturing process

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The phosphate groups serve as intermediary functional groups that can be incorporated into the polymer chain during synthesis, providing a standardized approach to creating adhesion-promoting polymers without requiring complex post-modification steps

Inventive Principle:
Principle #24Intermediary (Mediator)

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 adhesive demonstrates significant bonding strength comparable to commercial bone cements and is degradable, making it suitable for orthopaedic repairs and spinal cord injuries, with potential for use in bone-to-bone or bone-to-metal bonding.

Implementation Method 1

phosphate functionalized PEU polymers and copolymers crosslinked using one or more divalent metal crosslinking agents

Methodology Applied
Scientific EffectCoordinate bonding: Chemical Bonding

Implementation Method 2

Phosphate based compounds have been used as adhesion promoters for decades in underwater coatings, dental applications, bone implants

Methodology Applied
Scientific EffectIon attraction: Ion Repulsion/Attraction

Data Source

PatentEP3448307B1Phosphorylated poly(ester-urea) based degradable bone adhesives
Publication Date: 2023.07.26 THE UNIVERSITY OF AKRON
  • EP3448307B1 patent drawingFigure 1
  • EP3448307B1 patent drawingFigure 2A
  • EP3448307B1 patent drawingFigure 2B

AI summary

In various aspects, the present invention provides a degradable and resorbable novel phosphate functionalized amino acid-based poly(ester urea) adhesive and related methods for its synthesis and use. These adhesives are formed from phosphate functionalized PEU polymers and copolymers crosslinked using one or more divalent metal crosslinking agents. The phosphate functionalized amino acid-based poly(ester urea) adhesives of various embodiments of the present invention have been found particularly effective in bonding bone to either bone or metal and have demonstrated adhesive strengths on bone samples that were significant and comparable to commercially available poly(methyl methacrylate) bone cement.