Citrate Polymer Networks for Bone Scaffolds

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Solution Overview

Problem

Existing elastomeric polymers used in tissue engineering face challenges such as poor mechanical strength, inability to mimic native tissue properties, and limited antimicrobial effectiveness, particularly when used in porous scaffolds or in vivo, and struggle to effectively treat segmental bone defects due to inadequate mechanical strength and integration with surrounding tissue.

Innovation Solution

Development of citrate-containing polymer networks with high cross-linking density, capable of mimicking the mechanical properties of native tissues, and incorporating particulate inorganic materials like hydroxyapatite for enhanced mechanical strength and antimicrobial properties, using click chemistry to form azide-alkyne cycloaddition products for cross-linking and biofunctionalization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If elastomeric polymers are used to mimic native tissue elasticity, then biocompatibility is improved, but mechanical strength deteriorates

Engineering Contradiction:
ImprovebiocompatibilityVSAvoidmechanical strength
Core Design Contradiction:
Adaptability or versatilityVSStrength

Solution Approach 1:

The patent employs composite materials by combining elastomeric polymer matrices with reinforcing fillers such as nanocellulose, graphite oxide, and carbon nanotubes. This composite approach allows the material to maintain the elasticity and biocompatibility of the polymer while gaining the mechanical strength and structural integrity provided by the reinforcing agents.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent applies local quality by creating regions of different properties within the scaffold structure. The polymer matrix provides elasticity and biocompatibility in certain regions, while concentrated reinforcing agents provide localized mechanical strength where needed, allowing the material to exhibit both soft tissue-like flexibility and structural durability.

Inventive Principle:
Principle #3Local quality

2Ease of operation

If polymers are molded into porous scaffolds for tissue engineering, then cell infiltration is improved, but mechanical strength deteriorates

Engineering Contradiction:
Improvecell infiltrationVSAvoidmechanical strength
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The patent utilizes porous materials by designing scaffolds with controlled pore structures that facilitate cell infiltration and tissue growth. The porous architecture allows cells to migrate into the scaffold and establish themselves, while the reinforcing agents embedded within the porous structure maintain mechanical strength despite the reduced material density.

Inventive Principle:
Principle #31Porous materials

Solution Approach 2:

The composite material system enables the creation of porous scaffolds with enhanced mechanical properties. The reinforcing agents such as nanocellulose and carbon nanotubes are distributed within the porous polymer matrix, providing structural support that compensates for the strength loss associated with porosity while maintaining high cell infiltration capability.

Inventive Principle:
Principle #40Composite materials

3Object-affected harmful factors

If antibiotics are coated onto polymers for antimicrobial protection, then antimicrobial effectiveness is improved, but mechanical performance deteriorates

Engineering Contradiction:
Improveantimicrobial effectivenessVSAvoidmechanical performance
Core Design Contradiction:
Object-affected harmful factorsVSStrength

Solution Approach 1:

The patent merges the antimicrobial function with the structural polymer matrix by incorporating antimicrobial agents directly into the polymer composition during manufacturing. This integration allows the material to provide both mechanical support and antimicrobial protection as a unified structure, eliminating the need for separate coatings that would compromise mechanical performance.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The composite material approach combines the polymer matrix with antimicrobial agents and reinforcing agents in a single integrated system. The antimicrobial components are distributed within the composite structure, providing protective functionality without forming separate coating layers that would weaken the mechanical properties of the scaffold.

Inventive Principle:
Principle #40Composite materials

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 citrate-based polymer networks provide mechanical stability and structural integrity similar to native tissues, promote bone regeneration, and exhibit improved antimicrobial properties, effectively treating segmental bone defects with enhanced biocompatibility and integration, while maintaining mechanical strength and reducing inflammatory responses.

Implementation Method 1

azide and alkyne groups, reactive under physiological conditions to form cross-linked polymer networks

Methodology Applied
Scientific EffectClick chemistry: Chemical Bonding

Implementation Method 2

elastomeric polymers to mimic the elastic nature of many human soft tissues

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP4001342B1Bioelastomers and applications thereof
Publication Date: 2024.08.21 THE PENN STATE RES FOUND INC
  • EP4001342B1 patent drawingFigure 1
  • EP4001342B1 patent drawingFigure 2(A)
  • EP4001342B1 patent drawingFigure 2(B)

AI summary

In one aspect, compositions are described herein. In some embodiments, a composition described herein comprises the reaction product of (i) citric acid, a citrate, or an ester of citric acid with (ii) a polyol, and (iii) a monomer comprising one or more alkyne moieties and/or azide moieties. The reaction product, in some instances, comprises a polymer. Further, in some cases, a composition described herein comprises a plurality of polymers. In some embodiments, the polymers are selected to be reactive with one another through a click chemistry reaction scheme to form a polymer network. In another aspect, medical implants and medical devices are described herein, the implants and devices comprising a polymer or polymer network described herein.