Biphasic CAP/HAP Bone Substitute with Epitaxial HAP Layer
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Solution Overview
Problem
Existing calcium phosphate/hydroxyapatite (CAP/HAP) bone substitute materials face issues with accelerated degradation in vivo due to differences in solubility, leading to local calcium ion oversaturation and increased osteoclast activity, potentially causing adverse inflammation reactions.
Innovation Solution
A biphasic CAP/HAP bone substitute material with a sintered CAP core and a closed epitactically grown layer of nanocrystalline HAP, featuring a homogeneous coarse external surface, is developed, where the epitactically grown nanocrystals have the same size and morphology as human bone mineral, and the thickness of the HAP layer controls the rate of calcium release to maintain a stable calcium equilibrium.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If CAP/HAP systems are used as bone substitute materials, then bone formation and regeneration are promoted, but accelerated degradation occurs due to higher solubility of TCP compared to HAP
Solution Approach 1:
The invention uses a composite material system combining TCP and HAP in specific ratios (e.g., 60:40, 70:30, 80:20 by weight). This composite structure allows the material to exhibit both the osteogenic properties of TCP and the stability of HAP, resolving the contradiction between promoting bone formation and preventing accelerated degradation.
Solution Approach 2:
The invention modifies the chemical composition parameters of the bone substitute material by controlling the ratio of TCP to HAP and adjusting the particle size distribution (D10, D50, D90). These parameter changes optimize the balance between solubility for bone regeneration and stability to prevent excessive degradation.
2Reliability
If TCP is used to promote bone regeneration, then osteogenic activity is enhanced, but local calcium ion oversaturation occurs leading to increased osteoclast activity
Solution Approach 1:
HAP acts as an intermediary substance that modulates the calcium release from TCP. The HAP component controls the solubility and ion release rate, preventing local calcium oversaturation while still allowing sufficient calcium for osteogenic differentiation. This intermediary effect resolves the contradiction between enhancing osteogenic activity and avoiding harmful calcium imbalance.
3Productivity
If synthetic bone substitute material is used, then bone replacement is achieved, but adverse inflammation reactions occur due to accelerated resorption
Solution Approach 1:
The invention changes the particle size parameters (D10, D50, D90 distribution) and chemical composition (TCP:HAP ratio) to optimize the material's performance. These parameter adjustments control the degradation rate and ion release, enabling efficient bone replacement while minimizing adverse inflammation reactions by preventing excessive resorption.
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 material promotes enhanced osteogenic differentiation of fetal human mesenchymal stem cells, indicating an improved in vivo osteogenic response with reduced risk of adverse inflammation reactions by maintaining a stable calcium environment conducive to bone regeneration.
Implementation Method 1
the transformation process of CAP to HAP
Implementation Method 2
closed epitactically grown layer of nanocrystalline HAP deposited on the external surface
Implementation Method 3
Chemical dissolution and biological resorption by cells. Both processes cause dissolution of the ceramic material
Data Source
AI summary
A biphasic calcium phosphate/hydroxyapatite (CAP/HAP) bone substitute material having a sintered CAP core and a closed epitactically grown layer of nanocrystalline HAP deposited on the external surface of the sintered CAP core, wherein the closed epitactically grown layer of nanocrystalline HAP deposited on the external surface of the sintered CAP core has a homogeneous coarse external surface comprising flat crystal platelets, which shows an enhanced osteogenic response, a method of promoting bone formation, bone regeneration and/or bone repair by implanting the biphasic calcium phosphate/hydroxyapatite (CAP/HAP) bone substitute material, and a process of preparation thereof.