Epitaxial HAP Coated CAP Core for Bone Substitute Stability
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Solution Overview
Problem
Current biphasic calcium phosphate/hydroxyapatite (CAP/HAP) bone substitute materials face issues with accelerated degradation in vivo due to differences in thermodynamic stability, leading to increased osteoclast activity and adverse inflammation reactions, as the solubility of TCP is higher than HAP, disrupting the natural calcium equilibrium.
Innovation Solution
A biphasic CAP/HAP bone substitute material with a sintered CAP core and a closed epitactically grown layer of nanocrystalline HAP, where the epitactically grown nanocrystals have a homogeneous coarse external surface comprising flat crystal platelets, is developed, promoting a stable calcium release and enhancing osteogenic differentiation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a biphasic CAP/HAP bone substitute material is used, then bone regeneration is promoted through osteoconduction, but accelerated degradation occurs due to solubility differences between TCP and HAP
Solution Approach 1:
The patent changes the surface morphology parameter of the HAP layer from conventional smooth or irregular surfaces to a specifically engineered coarse surface with controlled roughness. This coarse surface structure modifies the dissolution kinetics of the material, allowing TCP to degrade at a controlled rate that matches HAP degradation, preventing calcium ion oversaturation while maintaining osteoconductive properties for bone regeneration
Solution Approach 2:
The patent creates a composite structure consisting of a sintered CAP core (providing bulk structural support and controlled degradation) covered by an epitactically grown HAP layer with coarse surface (providing osteoconductive interface and modified dissolution kinetics). This composite architecture synergistically combines the resorbable properties of TCP with the stability of HAP, achieving both bone regeneration promotion and prolonged material stability
2Reliability
If TCP is used in the biphasic system, then osteoconduction is enhanced, but calcium equilibrium is disrupted leading to increased osteoclast activity
Solution Approach 1:
The patent modifies the surface morphology parameter of the HAP layer to create a coarse surface structure. This surface modification slows down the dissolution rate of the CAP/HAP material system, preventing excessive calcium ion release that would disrupt calcium equilibrium and trigger osteoclast activity, while preserving the osteoconductive functionality needed for bone regeneration
Solution Approach 2:
The patent creates a feedback-controlled degradation system where the coarse HAP surface structure regulates calcium ion release rates. The modified surface morphology provides a feedback mechanism that maintains calcium ion concentration within physiological ranges, preventing the positive feedback loop that leads to osteoclast activation and inflammatory responses
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 supports a stable calcium release, reducing osteoclast activity and inflammation, while enhancing bone regeneration by promoting a favorable calcium equilibrium and increased osteogenic differentiation.
Implementation Method 1
a closed epitactically grown layer of nanocrystalline HAP deposited on the external surface of the sintered CAP core
Implementation Method 2
collagen matrix or granulate blend of bone substitute material
Data Source
Figure 1a~1b
Figure 2a~2e
Figure 3a~3b
AI summary
The invention concerns: - A collagen matrix, in particular for use as a putty, a strip or a plug, comprising particles of a biphasic calcium phosphate/hydroxyapatite (CAP/HAP) bone substitute material comprising a sintered CAP core and a closed epitactically grown layer of nanocrystalline HAP deposited on the external surface of the sintered CAP core, whereby the epitactically grown nanocrystals have the same size and morphology as human bone mineral, 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, - a process for preparing that collagen matrix, and - a granulate blend comprising particles of such a biphasic bone material.