Bone-adhesive sheet with calcium-binding polymer

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Solution Overview

Problem

Current biomaterials for bone repair lack specific adhesion to bone tissue, leading to poor control over degradation rates, mechanical properties, and biological mechanisms governing tissue reconstruction, and they often rely on rigid non-degradable materials with long-term instability and infection risks.

Innovation Solution

A biocompatible, flexible bone-adhesive sheet with a cohesive fibrous carrier structure and water-soluble calcium-binding polymer particles or reactive particles that form hydrogels upon wetting, enabling strong bonding to bone tissue by forming reversible cross-links with Ca2+ ions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If rigid non-degradable materials are used for bone fixation, then mechanical strength is improved, but long-term stability and biocompatibility deteriorate due to infection risks and lack of degradation control

Engineering Contradiction:
Improvemechanical strengthVSAvoidlong-term stability
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent changes the material parameters from rigid non-degradable to flexible degradable polymers with controlled degradation rates. The bone-adhesive sheet uses water-soluble calcium-binding polymers that degrade at controlled rates, transitioning from static mechanical support to dynamic biological integration over time.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention creates a composite structure combining a fibrous carrier structure with polymer particles containing calcium-binding groups. This composite enables both initial mechanical support through the fibrous structure and controlled degradation through the polymer particles, resolving the contradiction between strength and long-term stability.

Inventive Principle:
Principle #40Composite materials

2Stability of the object's composition

If barrier membranes are used to separate soft tissue from bone, then tissue reconstruction control is improved, but adhesive properties deteriorate due to lack of specific bone adhesion

Engineering Contradiction:
Improvecontrol over tissue reconstructionVSAvoidadhesive properties
Core Design Contradiction:
Stability of the object's compositionVSStrength

Solution Approach 1:

The patent applies local quality by incorporating calcium-binding groups (such as bisphosphonates, citrate, or EDTA) specifically within the polymer particles distributed throughout the fibrous carrier. This localized functionalization provides specific bone-adhesive properties at the tissue interface while maintaining the barrier function for tissue reconstruction control.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The invention changes the chemical parameters of the barrier membrane by incorporating water-soluble polymers with calcium-binding capabilities. These polymers form reversible cross-links with Ca2+ ions in bone tissue, creating strong adhesive bonds that enable both barrier function and specific bone attachment.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If degradable polymers are used for bone repair, then biocompatibility is improved, but mechanical properties deteriorate due to poor control over degradation rates

Engineering Contradiction:
ImprovebiocompatibilityVSAvoidmechanical properties
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent applies dynamics by using degradable polymers that transition from providing mechanical support to being fully degraded and absorbed by the body. The controlled degradation rate allows the material to dynamically adapt its mechanical properties over time, maintaining strength when needed and degrading as bone heals, thereby achieving both biocompatibility and adequate mechanical properties.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes the degradation parameters of the polymers by selecting from various water-soluble polymers (polyoxazolines, polyethylene glycols, polyvinylpyrrolidones, polyurethanes) with different degradation rates. The calcium-binding groups further modulate degradation kinetics through reversible cross-linking with Ca2+ ions, enabling tailored mechanical properties that maintain strength while ensuring biocompatibility.

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 bone-adhesive sheet effectively prevents fast-regenerating soft tissues from growing into bone tissue, providing excellent adhesive properties, flexibility for irregularly shaped sites, and rapid bonding to bone, while being biodegradable and minimizing bending friction.

Implementation Method 1

a water-soluble calcium-binding polymer carrying at least one calcium-binding group selected from bisphosphonate, citrate, ethylenediaminetetraacetic acid (EDTA) and combinations thereof... wherein calcium-binding group is a group that is capable of forming two or more separate coordinate bonds with Ca 2+

Methodology Applied
Scientific EffectCoordinate bonding: Chemical Bonding

Implementation Method 2

The polymer particles or the combination of reactive particles and bisphosphonate particles may be distributed homogeneously throughout the bone-adhesive sheet, thereby minimising bending friction.

Methodology Applied
Scientific EffectCalcium binding: Adsorption

Data Source

PatentEP4188466B1Bone-adhesive sheet
Publication Date: 2024.12.25 CILAG GMBH INTERNATIONAL

AI summary

The invention relates to a biocompatible, flexible, bone-adhesive sheet that may suitably be applied in the treatment of bone defects, said bone-adhesive sheet comprising: · a cohesive fibrous carrier structure comprising a three-dimensional interconnected interstitial space; • distributed within the interstitial space, (i) a plurality of polymer particles comprising a water-soluble calcium-binding polymer, said water-soluble calcium-binding polymer carrying at least one calcium binding group or (ii) a plurality of reactive particles comprising an electrophilically activated water-soluble polymer and a plurality of bisphosphonate particles comprising nitrogenous bisphosphonate.