Core-Shell Bioactive Scaffold for Bone Regeneration

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Solution Overview

Problem

Current tissue engineering scaffolds for bone and osteochondral tissue regeneration lack mechanical strength and durability, and are limited by the use of chemically compatible materials that restrict the modulation of their characteristics, particularly mechanical properties, and often fail to promote effective vascularization and long-term tissue regeneration.

Innovation Solution

An integrated core-shell bioactive structure comprising a porous core of biocompatible and biodegradable thermoplastic polymers, coated with a hydrogel formed from a polypeptide, a water-soluble polymer, and an aminated polysaccharide, which includes additional components like mesenchymal stromal cells and growth factors to enhance osteo-inductive capacity and mechanical support, allowing for modulated porosity and mechanical characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If chemically compatible materials are used in core-shell scaffolds, then material stability is improved, but mechanical strength and durability deteriorate

Engineering Contradiction:
Improvematerial stabilityVSAvoidmechanical strength
Core Design Contradiction:
Stability of the object's compositionVSStrength

Solution Approach 1:

The patent employs composite materials by combining a thermoplastic polymer core with a hydrogel shell composed of multiple components (polypeptide, water-soluble polymer, and aminated polysaccharide). This composite structure allows each material to contribute its strengths: the thermoplastic core provides mechanical strength and structural stability, while the hydrogel shell offers bioactivity, porosity control, and degradation control. The composite nature resolves the contradiction by integrating materials with complementary properties rather than relying on single-material solutions.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The scaffold is segmented into distinct core and shell regions with different material compositions and functions. The core contains the thermoplastic polymer providing mechanical integrity, while the shell contains the hydrogel providing bioactive functionality. This segmentation allows independent optimization of each region's properties, enabling the overall structure to achieve both stability and strength simultaneously.

Inventive Principle:
Principle #1Segmentation

2Reliability

If porosity is increased to promote cell colonization, then tissue regeneration is improved, but mechanical strength deteriorates

Engineering Contradiction:
Improvetissue regenerationVSAvoidmechanical strength
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

Different regions of the scaffold have different porosity characteristics optimized for their specific functions. The core region maintains lower porosity to preserve mechanical strength, while the shell region exhibits higher porosity to facilitate cell infiltration, nutrient transport, and tissue regeneration. This local differentiation of porosity resolves the contradiction by applying appropriate porosity levels where needed without compromising overall structural integrity.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The composite structure of thermoplastic core and hydrogel shell enables simultaneous achievement of strength and porosity. The thermoplastic core provides the mechanical framework with controlled porosity, while the hydrogel shell contributes additional porosity and bioactivity for tissue regeneration. The composite nature allows the structure to exhibit both high strength and high porosity that would be difficult to achieve with a single material.

Inventive Principle:
Principle #40Composite materials

3Duration of action of stationary object

If resorbable materials are used, then long-term durability is improved, but mechanical support during regeneration deteriorates

Engineering Contradiction:
Improvelong-term durabilityVSAvoidmechanical support
Core Design Contradiction:
Duration of action of stationary objectVSStrength

Solution Approach 1:

The scaffold exhibits dynamic mechanical properties that evolve over time. Initially, the thermoplastic core provides high mechanical strength to support the tissue during early regeneration phases. As regeneration progresses, the controlled degradation of the resorbable materials occurs, gradually transferring mechanical load to the newly formed tissue. This dynamic adaptation resolves the contradiction by providing strong support when needed and allowing degradation when tissue is ready to assume the load.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The scaffold is designed to perform its mechanical support function in advance before complete degradation occurs. The thermoplastic core maintains structural integrity throughout the regeneration process, providing preliminary and sustained mechanical support. The controlled degradation rate ensures that the scaffold remains mechanically competent until the regenerated tissue can independently bear physiological loads, preventing premature structural failure.

Inventive Principle:
Principle #10Preliminary action

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 core-shell structure provides sufficient mechanical consistency for bone tissue regeneration, supports rapid colonization by cells, and promotes osteogenesis, with a controlled resorption rate that matches the regrowth timeline, offering a more effective and durable solution for tissue repair.

Implementation Method 1

a core coating, in an amount between 1 and 99% by weight of the structure, comprising a hydrogel formed by reaction of a polypeptide either derived from natural tissues or synthetic, a water-soluble polymer functionalized so as to be capable of reacting with the polypeptide

Methodology Applied
Scientific EffectChemical bonding: Chemical Bonding

Implementation Method 2

a porous core made of a biocompatible and biodegradable thermoplastic polymer

Methodology Applied
Scientific EffectDiffusion: Diffusion

Data Source

PatentEP4178634B1Integrated core-shell bioactive structure for the regeneration of bone and osteochondral tissues
Publication Date: 2024.07.17 LE RONDINI - CITTA DI LUMEZZANE ONLUS
  • EP4178634B1 patent drawingFigure 1~3
  • EP4178634B1 patent drawingFigure 4
  • EP4178634B1 patent drawingFigure 5~6

AI summary

An integrated core-shell bioactive structure which is used in the field of tissue engineering to promote tissue regeneration, in particular of bone and osteochondral tissues, and a process for the production thereof are described.