Collagen Microsphere Annulus Plug for Disc Injection Leakage

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Solution Overview

Problem

Current methods for intra-discal injection of biomolecules and mesenchymal stem cells into intervertebral discs face significant challenges due to leakage and backflow caused by high intra-discal pressure, resulting in low cell retention and the formation of osteophytes, which compromises the efficacy and safety of cell-based therapies.

Innovation Solution

A medical apparatus featuring a photochemically crosslinked type I collagen matrix and glycosaminoglycan composite annulus plug is used to block the injection portal, preventing leakage by expanding to fill the space created during injection, thereby enhancing the retention of therapeutic agents within the disc.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If hydrogels made of natural or synthetic biomaterials are used for intra-discal injection, then the injection can be performed, but the hydrogels have insufficient viscosity and stiffness resulting in immediate loss of majority of injected cells due to backflow

Engineering Contradiction:
Improvecell retentionVSAvoidviscosity and stiffness
Core Design Contradiction:
Quantity of substanceVSStrength

Solution Approach 1:

The patent uses composite materials by combining hydrogel with collagen microspheres to create a material system with enhanced viscosity and stiffness. The collagen microspheres provide structural support and increase the overall rigidity of the injection mixture, preventing backflow while maintaining cell viability and retention within the intervertebral disc.

Inventive Principle:
Principle #40Composite materials

2Stress or pressure

If high intra-discal pressure is present, then the disc structure is maintained, but leakage or backflow of injected materials occurs through the injection portal

Engineering Contradiction:
Improveintra-discal pressureVSAvoidleakage prevention
Core Design Contradiction:
Stress or pressureVSReliability

Solution Approach 1:

The patent applies preliminary action by pre-forming collagen microspheres that are suspended in the hydrogel injection mixture. These microspheres are prepared in advance to provide immediate structural support upon injection, creating a plug-like effect at the injection portal that prevents leakage caused by high intra-discal pressure before the injection is even completed.

Inventive Principle:
Principle #10Preliminary action

3Adaptability or versatility

If mesenchymal stem cells are injected into degenerative discs, then cell-based therapy can be performed, but low cell retention and significant cell leakage occur

Engineering Contradiction:
Improvecell-based therapy capabilityVSAvoidcell retention
Core Design Contradiction:
Adaptability or versatilityVSQuantity of substance

Solution Approach 1:

The patent uses hydrogel and collagen microspheres as intermediary materials that carry and protect mesenchymal stem cells during injection. The hydrogel provides a protective matrix that holds the cells, while the collagen microspheres reinforce this matrix to prevent leakage. This intermediary system enables cell-based therapy to be performed effectively while maintaining high cell retention within the target disc.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Productivity

If cell suspension is injected under high pressure, then injection can be completed, but formation of osteophytes occurs due to cell leakage

Engineering Contradiction:
Improveinjection completionVSAvoidosteophyte formation
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent converts the harmful effect of high intra-discal pressure, which normally causes leakage and osteophyte formation, into a beneficial force. The collagen microspheres are designed to pack and form a dense plug under pressure, transforming the high-pressure environment that causes harm into a condition that enhances the sealing effect and prevents cell leakage, thereby eliminating osteophyte formation.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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 annulus plug significantly reduces cell leakage and osteophyte formation, improving the retention of injected materials and facilitating the clinical translation of mesenchymal stem cell-based therapies for disc degeneration by maintaining therapeutic agents within the intervertebral discs.

Implementation Method 1

A medical apparatus featuring a photochemically crosslinked type I collagen matrix and glycosaminoglycan composite annulus plug

Methodology Applied
Scientific EffectPhotochemical crosslinking: Photopolymerisation

Data Source

PatentEP2861188B1Materials for filling biological cavities and preventing leakage of injected therapeutic agents
Publication Date: 2021.03.17 THE UNIVERSITY OF HONG KONG
  • EP2861188B1 patent drawingFigure 1A~1I
  • EP2861188B1 patent drawingFigure 2A~2M
  • EP2861188B1 patent drawingFigure 3A~3E

AI summary

The subject invention pertains to medical apparatuses and methods for reducing or preventing leakage of injected therapeutic agents (including liquid-containing substances, cells) into a solid or hollow tissue/organ after puncturing.