Injectable Polycaprolactone Foam for Bone Defect Fusion

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Solution Overview

Problem

Current bone adhesives face challenges in biocompatibility, mechanical integrity, and bioactivity, with synthetic adhesives lacking biodegradability and biocompatibility, and biologically inspired materials failing to provide mechanical stability required for bone tissue applications.

Innovation Solution

An injectable and expandable composition comprising polycaprolactone particles coated with polydopamine and bound to polymethacrylic acid, which enhances bioactive and adhesive properties, suitable for bone regeneration and tissue engineering, and can be administered as a biodegradable material for treating bone defects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If synthetic adhesives are used, then adhesive strength is improved, but biocompatibility deteriorates

Engineering Contradiction:
Improveadhesive strengthVSAvoidbiocompatibility
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The invention uses a composite material system combining polycaprolactone (synthetic polymer providing mechanical strength and adhesion) with polydopamine (biologically inspired coating providing bioactivity and biocompatibility). This composite structure allows the synthetic adhesive to maintain its adhesive strength while the polydopamine coating layer provides the biocompatible interface with bone tissue, effectively resolving the contradiction between adhesive strength and biocompatibility.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The polydopamine coating is applied locally on the surface of polycaprolactone particles, creating a layered structure where different regions have different functions. The inner polycaprolactone core provides adhesive strength and structural integrity, while the outer polydopamine shell provides bioactivity and biocompatibility. This local differentiation allows simultaneous achievement of both adhesive strength and biocompatibility.

Inventive Principle:
Principle #3Local quality

2Object-affected harmful factors

If biologically inspired materials are used, then biocompatibility is improved, but mechanical integrity deteriorates

Engineering Contradiction:
ImprovebiocompatibilityVSAvoidmechanical integrity
Core Design Contradiction:
Object-affected harmful factorsVSStrength

Solution Approach 1:

The composite structure combines biologically inspired polydopamine (providing biocompatibility and bioactivity) with synthetic polycaprolactone (providing mechanical integrity). The polydopamine coating thickness is controlled at 0.5-5% of total composition, ensuring sufficient bioactivity while maintaining the mechanical properties dominated by the polycaprolactone core. This composite approach resolves the contradiction between biocompatibility and mechanical integrity.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The biologically inspired polydopamine is localized to the particle surface coating, where it interacts with bone tissue to provide biocompatibility and bioactivity. The bulk interior remains as polycaprolactone, maintaining mechanical integrity. This spatial separation of functions allows biologically inspired materials to provide biocompatibility without compromising overall mechanical strength.

Inventive Principle:
Principle #3Local quality

3Stability of the object's composition

If polycaprolactone particles are used, then mechanical stability is improved, but bioactivity deteriorates

Engineering Contradiction:
Improvemechanical stabilityVSAvoidbioactivity
Core Design Contradiction:
Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

The polycaprolactone particles form the stable structural core providing mechanical stability, while the polydopamine coating applied locally on the particle surfaces provides the bioactive interface for bone interaction. This local functional differentiation allows the bulk material to maintain mechanical stability while the surface layer provides bioactivity for bone regeneration.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The composite of polycaprolactone particles coated with polydopamine creates a material where the synthetic polymer provides mechanical stability and the biologically inspired coating provides bioactivity. The controlled coating ratio (0.5-5% polydopamine) ensures sufficient bioactivity is introduced without compromising the mechanical stability of the polycaprolactone framework.

Inventive Principle:
Principle #40Composite materials

4Strength

If adhesive coating is added to particles, then adhesive properties are improved, but device complexity deteriorates

Engineering Contradiction:
Improveadhesive propertiesVSAvoiddevice complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The polydopamine coating is applied using self-polymerization of dopamine monomers on the polycaprolactone particle surfaces, a self-service process that does not require complex external equipment or multi-step procedures. The dopamine spontaneously polymerizes and adheres to the particle surfaces under controlled conditions, providing adhesive coating through a relatively simple process that avoids significant device complexity.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The adhesive properties are enhanced by controlling the concentration and thickness parameters of the polydopamine coating (0.5-5% of total composition), rather than by complex device design. By optimizing these material parameters, the adhesive properties are improved through material composition control rather than through complex application devices or procedures.

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 composition achieves improved bioactive and adhesive properties, providing mechanical stability and bioactivity, suitable for diverse trauma and pathology-driven needs in bone surgery, with enhanced integration and regeneration capabilities.

Implementation Method 1

bone particles and polycaprolactone which foams upon heating

Methodology Applied
Scientific EffectFoaming upon heating: Phase Change

Implementation Method 2

polycaprolactone which foams upon heating

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 3

polydopamine adhesive bound to said filler

Methodology Applied
Scientific EffectAdhesion: Adhesive

Implementation Method 4

polymethacrylic acid plasticizer bound to said polydopamine adhesive

Methodology Applied
Scientific EffectPlasticization: Plasticity

Data Source

PatentEP3743122B1Injectable and expandable composition, devices, kits, methods and uses thereof
Publication Date: 2022.12.07 ASSOC FOR THE ADVANCEMENT OF TISSUE ENG & CELL BASED TECH & THERAPIES A4TEC
  • EP3743122B1 patent drawingFigure 1~2
  • EP3743122B1 patent drawingFigure 3
  • EP3743122B1 patent drawingFigure 4A~4B

AI summary

The present disclosure relates to injectable and expandable compositions, devices, kits and methods for use in an approach for the in-situ foaming of polymers for bone or tissue defects, namely to fill and/or fuse a tissue defect. The present disclosure relates to compositions, devices, kits and methods for use in an approach for the in-situ foaming of polymers for bone or tissue defects, namely for bone tissue defect filling/fusion. The design of extrudable and expandable compositions for bone fusion is one of the most challenging fields in the intersection of polymer and biomedical engineering. An aspect of the present disclosure relates to an injectable expandable composition for use in medicine, veterinary or cosmetic, comprising a polycaprolactone particle filler; a polydopamine adhesive bound to said filler; a polymethacrylic acid plasticizer bound to said polydopamine adhesive.