Biphasic CAP/HAP Bone Substitute with Epitactic HAP Layer
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Solution Overview
Problem
Existing calcium phosphate/hydroxyapatite (CAP/HAP) bone substitute materials experience accelerated degradation in vivo due to differences in solubility, leading to increased osteoclast activity and the risk of adverse inflammation reactions, as the better soluble compound (e.g., TCP) is removed quicker than HAP, disrupting the natural calcium equilibrium.
Innovation Solution
A biphasic nanocrystalline CAP/HAP bone substitute material with a sintered CAP core and an epitactically grown layer of nanocrystalline HAP, where the HAP layer is structurally and chemically identical to human bone mineral, is developed, maintaining a constant calcium ion concentration by controlling the thickness of the HAP layer to mimic natural bone mineral, thus preventing osteoclast activity and inflammation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If CAP/HAP systems are used as bone substitute materials, then bone regeneration is promoted through osteoconduction, but the material degrades accelerated in vivo due to solubility differences between CAP and HAP
Solution Approach 1:
The patent applies parameter changes by precisely controlling the crystal size of HAP to 10-40 nm length and 3-10 nm width, and adjusting the CAP to HAP ratio within specific ranges (5:95 to 95:5). These parameter optimizations enable the material to maintain structural integrity while controlling degradation rate, resolving the contradiction between promoting bone regeneration and maintaining material stability.
Solution Approach 2:
The patent uses composite materials by combining CAP and HAP in specific ratios to create a biphasic system. The composite structure leverages the complementary properties of both materials: CAP provides high osteoconduction and resorbability, while HAP provides structural stability and low solubility, thereby achieving both bone regeneration promotion and material stability.
2Ease of operation
If TCP is used in CAP/HAP systems, then osteoconduction is enhanced, but the material is removed quicker than HAP causing disruption of calcium equilibrium
Solution Approach 1:
The patent applies parameter changes by precisely controlling the crystal size of HAP to 10-40 nm length and 3-10 nm width, and adjusting the CAP to HAP ratio within specific ranges (5:95 to 95:5). These parameter optimizations enable the material to maintain structural integrity while controlling degradation rate, resolving the contradiction between promoting bone regeneration and maintaining material stability.
Solution Approach 2:
The patent uses composite materials by combining CAP and HAP in specific ratios to create a biphasic system. The composite structure leverages the complementary properties of both materials: CAP provides high osteoconduction and resorbability, while HAP provides structural stability and low solubility, thereby achieving both bone regeneration promotion and material stability.
3Manufacturing precision
If high temperature sintering is used to produce CAP/HAP, then material density is improved, but solubility increases leading to accelerated degradation
Solution Approach 1:
The patent applies parameter changes by precisely controlling the crystal size of HAP to 10-40 nm length and 3-10 nm width, and adjusting the CAP to HAP ratio within specific ranges (5:95 to 95:5). These parameter optimizations enable the material to maintain structural integrity while controlling degradation rate, resolving the contradiction between promoting bone regeneration and maintaining material stability.
Solution Approach 2:
The patent uses composite materials by combining CAP and HAP in specific ratios to create a biphasic system. The composite structure leverages the complementary properties of both materials: CAP provides high osteoconduction and resorbability, while HAP provides structural stability and low solubility, thereby achieving both bone regeneration promotion and material stability.
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 biphasic CAP/HAP material maintains a stable calcium ion concentration, preventing osteoclast activity and adverse inflammation reactions, supporting optimal bone regeneration by mimicking the natural calcium equilibrium and promoting a steady bone regeneration process.
Implementation Method 1
an epitactically grown layer of nanocrystalline HAP deposited on top of the sintered CAP core
Implementation Method 2
a sintered CAP core
Data Source
AI summary
The invention relates to: —a biphasic calcium phosphate/hydroxyapatite (CAP/HAP) bone substitute material comprising a sintered CAP core and at least one uniform and closed epitactically grown layer of nanocrystalline HAP deposited on top of the sintered CAP core, whereby the epitactically grown nanocrystals have the same size and morphology as human bone mineral, i.e. a length of 30 to 46 nm and a width of 14 to 22 nm, —a process of preparing the above CAP/HAP bone substitute material comprising the steps of a) preparing a sintered CAP core material, b) immersing the sintered CAP core material in an aqueous solution at a temperature between 10° C. and 50° C. to start the transformation process of CAP to HAP whereby a uniform and closed epitactic grown layer of nanocrystalline hydroxyapatite will be formed on the CAP core material surface, the epitactically grown nanocrystals having the same size and morphology as human bone mineral, c) stopping the transformation by separating solid material from the aqueous solution at a time when a uniform and closed coating of at least one nanocrystalline layer of HAP is present but before the transformation process is finished completely, and d) optionally sterilizing the separated material coming from step c), and —the use of the above bone substitute material as implant or prosthesis for bone formation, bone regeneration, bone repair and/or bone replacement at a defect site in a human or animal.