Alginate Hydrogel Tissue Regeneration via Controlled Cross-Linking

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Solution Overview

Problem

Current methods for regenerating articular tissues like intervertebral discs face challenges in biocompatibility and mechanical characteristics, particularly in replacing the nucleus pulposus, with existing elastomers being too hard and invasive treatments required for cell scaffolding systems.

Innovation Solution

A biocompatible composition comprising a hydrogel matrix with sodium alginate and cells, cross-linked by a controlled release of a cross-linking agent from biodegradable polymeric particles, along with growth factors and extracellular matrix molecules, to create a three-dimensional structure for minimally invasive tissue regeneration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If elastomers are used to replace the nucleus pulposus, then the material can provide elasticity and resilience, but the materials are too hard and lack biocompatibility

Engineering Contradiction:
Improvemechanical characteristicsVSAvoidbiocompatibility
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The patent changes the material parameters by using hydrogels with controlled cross-linking density and composition (natural polymers like alginate, gelatin, chitosan) to achieve the right balance of elasticity, resilience, and biocompatibility, avoiding the excessive hardness of conventional elastomers

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates composite hydrogel materials combining multiple natural polymers (alginate, gelatin, chitosan) with cross-linking agents and growth factors to achieve both mechanical properties and biocompatibility simultaneously

Inventive Principle:
Principle #40Composite materials

2Reliability

If cell scaffolding systems are used for tissue regeneration, then tissue regeneration can be achieved, but invasive treatments are required

Engineering Contradiction:
Improvetissue regenerationVSAvoidsurgical invasiveness
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent uses hydraulic injection methods to deliver the hydrogel composition through minimally invasive procedures, allowing the material to be injected into the nucleus pulposus space through small incisions rather than requiring complex scaffolding implantation surgery

Inventive Principle:
Principle #29Pneumatics and hydraulics

Solution Approach 2:

The hydrogel composition contains growth factors and cells that autonomously promote tissue regeneration without requiring external scaffolding structures or complex surgical intervention, enabling the material to self-assemble and stimulate healing

Inventive Principle:
Principle #25Self-service

3Strength

If cross-linking agents are added to the hydrogel matrix, then mechanical resistance is improved, but biocompatibility may be compromised

Engineering Contradiction:
Improvemechanical resistanceVSAvoidbiocompatibility
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The patent uses natural polymer cross-linking agents (such as calcium ions, glutaraldehyde in controlled amounts, or enzymatic cross-linking) that act as intermediaries to create cross-linked hydrogel structures while maintaining biocompatibility through natural chemical bonds rather than harsh synthetic cross-linkers

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent controls the cross-linking parameters (cross-linking agent concentration, cross-linking conditions, hydrogel composition) to achieve optimal mechanical resistance while preserving biocompatibility through controlled, mild cross-linking processes

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 allows for effective, biocompatible regeneration of intervertebral disc nucleus pulposus, maintaining the annulus and cartilaginous plates' functionality, reducing surgical invasiveness, and promoting tissue recovery with controlled cross-linking and cellular induction.

Implementation Method 1

a cross linking agent adapted to cross-link at least one of said natural polymers in situ, thus giving to the biocompatible composition an appropriate resistance

Methodology Applied
Scientific EffectCross-linking: Chemical Bonding

Implementation Method 2

whose main characteristic is that the cross Linking agent is contained in biodegradable polymeric particles at controlled release, said biodegradable polymeric particles releasing said cross linking agent in a controlled way

Methodology Applied
Scientific EffectBiodegradation: Decomposition (biological)

Implementation Method 3

The main component of the amorphous connective tissue matrix of the core is a very hydrofilic polymer called 'aggrecane', belonging to the family of proteoglycanes, capable of absorbing a considerable amount of water and then of forming a matrix similar to a gel

Methodology Applied
Scientific EffectHydrophilicity: Hydrophile

Data Source

PatentEP1901791B1Biocompatible composition for replacing/regenerating tissues
Publication Date: 2012.08.15 CALVOSA GIUSEPPE

AI summary

A biocompatible composition for replacing/ regenerating articular tissues, in particular tissues of the nucleus pulposus but also not articular tissues such as bony tissues, providing a hydrogel matrix comprising a first and a second natural polymer, cells adapted to regenerate the tissue of the disc core, a cross linking agent suitable to cross-link at least one of said natural polymers in situ, thus giving to the biocompatible composition an appropriate resistance, and molecules adapted to stimulate the growth and/or the differentiation of cells, wherein one of the two natural polymers is sodium alginate. In a particular exemple, the above described composition before the cross-linking step has a starting density such that it is injectable. In particular, the cross linking action on sodium alginate is caused by a cross linking agent contained in biodegradable polymeric particles, released in a controlled way from natural polymers, for example gelatin, or starting from synthetic polymers, for example polylactic acid or copolymers of acid lactic-glycolic acid.