Calcium Phosphate Cement Adhesion via Polymer Interpenetrating Network
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Solution Overview
Problem
Calcium phosphate cements used as bone substitutes lack sufficient adhesive strength to effectively adhere or fix bones together, primarily due to insufficient chemical interaction with the bone surface or other materials, and lack the necessary strength for attaching bone to bone or bone to other materials.
Innovation Solution
A non-covalently bonded interpenetrating network is formed using small molecule multivalent metal compounds like tetracalcium phosphate (TTCP) reacting with amino acid phosphate compounds such as phosphoserine in an aqueous environment, creating a complex that enhances cohesive and adhesive properties by forming ionic and ion-dipole interactions with polymer surfaces, leading to durable materials with high intrinsic and extrinsic strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If calcium phosphate cements are used as bone substitutes, then bone void filling is achieved, but adhesive strength to bone and other materials is insufficient
Solution Approach 1:
The patent creates a composite material system consisting of calcium phosphate cement combined with polymer materials (such as polyethylene glycol, poly-L-lactic acid, or poly-D,L-lactic acid). This composite approach allows the cement to provide bone void filling while the polymer network provides enhanced adhesive strength and structural integrity, enabling both bone-to-bone and bone-to-material bonding capabilities
Solution Approach 2:
The patent modifies the chemical composition parameters of the cement by incorporating specific ratios of calcium phosphate particles (40-70 micrometers) with polymer solutions, adjusting the water-to-powder ratio, and controlling the setting time parameters to achieve optimal balance between workability, adhesive strength, and bonding performance
2Reliability
If calcium phosphate cements are used for bone void filling, then general filling function is achieved, but chemical interaction with bone surface is insufficient
Solution Approach 1:
The patent introduces polymer materials as intermediary substances that facilitate chemical interaction between the calcium phosphate cement and the bone surface. The polymers (particularly poly-L-lactic acid and poly-D,L-lactic acid) serve as mediators that enhance adhesion to bone collagen and hydroxyapatite, improving chemical bonding without requiring complex surface treatments or additional manufacturing steps
3Reliability
If marine species phosphoserine proteins are used for adhesion, then specific interaction with calcium hydroxyapatite is achieved, but compressive strength and surface area modification are insufficient at 0.5-5% concentration
Solution Approach 1:
The patent optimizes the concentration parameter of phosphoserine-containing polymers within the 0.5-5% weight range of the formulation, achieving the optimal balance between bone adhesion properties and compressive strength. This parameter optimization, combined with the specific polymer matrix, enables both appreciable bone adhesion and sufficient structural strength for clinical applications
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 interpenetrating network system achieves significant adhesion and bonding strength, allowing for temporary fixation of bone fragments during surgery, enhanced fracture fixation, and improved attachment of bone to other materials, including polymers and metals, with a tacky state that enables initial adherence without external force and a final hardened bond with high separation strength.
Implementation Method 1
The multivalent metal compounds and the amino acid phosphate compounds form a complex, interpenetrating network with the surface of polymer materials through ionic and ion-dipole interactions
Implementation Method 2
The multivalent metal compounds and the amino acid phosphate compounds form a complex, interpenetrating network with the surface of polymer materials through ionic and ion-dipole interactions
Implementation Method 3
These prior compositions have insufficient chemical interaction between the calcium phosphate composite and the bone surface or other surface materials
Data Source
Figure 1
Figure 2~3
AI summary
Certain small molecule amino acid phosphate compounds such as phosphoserine and certain multivalent metal compounds such as calcium phosphate containing cements have been found to have improved properties and form an interpenetrating network in the presence of a polymer that contain either an electronegative carbonyl oxygen atom of the ester group or an electronegative nitrogen atom of the amine group as the bonding sites of the polymer surfaces to the available multivalent metal ions.