Bone Material Surface Area Optimization
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Solution Overview
Problem
Current bone implant materials face challenges in optimizing bioresorption and bioactivity, as high surface area hydroxyapatite materials do not break down easily, while low surface area biphasic calcium phosphate materials resorb too quickly, leading to poor mechanical stability and incomplete bone regeneration.
Innovation Solution
A process to produce high surface area hydroxyapatite and low surface area biphasic calcium phosphate materials from natural bone mineral, optimizing surface area and protein content to enhance bioresorption and bioactivity, involving steps like degreasing, deproteinization, and controlled sintering to maintain geometric configurations similar to natural bone, while minimizing immunogenic responses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sintered hydroxyapatite materials are used in compact or porous form, then bone integration is improved, but the materials do not break down or resorb easily, prolonging the healing period
Solution Approach 1:
The patent changes the physical and chemical parameters of hydroxyapatite by controlling particle size distribution (bimodal or multimodal distribution with specific ranges), surface area (5-50 m²/g), and porosity (30-70%). These parameter adjustments enable the material to maintain structural integrity for bone integration while allowing controlled resorption over time, resolving the contradiction between reliability and healing duration.
Solution Approach 2:
The patent creates composite bone graft materials by combining hydroxyapatite with other biocompatible substances such as collagen, chitosan, or growth factors. This composite approach allows the material to maintain the bone integration properties of hydroxyapatite while incorporating resorbable components that facilitate controlled degradation and extend the healing process, thereby resolving the contradiction between durable bone integration and prolonged healing period.
2Duration of action of moving object
If tricalcium phosphates are used, then resorption rate is improved, but new bone formation cannot keep pace, creating voids filled by connecting tissue instead of bone
Solution Approach 1:
The patent adjusts the resorption rate parameter by controlling the hydroxyapatite crystal size, surface area, and phase composition. By optimizing these parameters, the material resorbs at a controlled pace that matches or is slightly slower than the bone formation rate, preventing void creation while maintaining adequate resorption to allow bone ingrowth, thus resolving the contradiction between resorption rate and bone regeneration quality.
Solution Approach 2:
The patent creates a dynamic system where the material properties evolve over time during the healing process. The controlled porosity and particle size distribution allow the material to progressively degrade as bone forms, creating a moving target for resorption that adapts to the healing stage. This dynamic approach ensures that resorption and bone formation remain synchronized, resolving the contradiction between adequate resorption and maintaining bone regeneration quality.
3Stability of the object's composition
If high temperature processing is used for BCP materials, then phase composition is improved, but surface area decreases and grains become coarse, which is not conducive for cellular activity
Solution Approach 1:
The patent employs low-temperature sintering (800-1000°C) combined with controlled atmosphere processing to achieve the desired biphasic calcium phosphate composition (hydroxyapatite and beta-tricalcium phosphate) without excessive grain growth. This parameter optimization maintains high surface area (5-50 m²/g) and fine grain structure while achieving stable phase composition, resolving the contradiction between phase stability and surface area retention.
Solution Approach 2:
The patent performs preliminary particle size reduction and surface preparation of the bone mineral before sintering. By pre-processing the raw material to achieve optimal particle size distribution and surface characteristics, the subsequent low-temperature sintering can achieve phase transformation without requiring high temperatures that would cause grain coarsening and surface area loss, thus resolving the contradiction between phase composition stability and surface area maintenance.
4Area of stationary object
If thermal treatments are reduced to maximize surface area, then bioactivity is improved, but purity, crystallinity and immunogenic response may be impacted
Solution Approach 1:
The patent optimizes the thermal treatment parameters by using moderate temperatures (800-1000°C) combined with extended treatment times or controlled atmospheric conditions. This parameter combination achieves sufficient purification and crystallinity development to reduce immunogenicity while limiting excessive grain growth that would reduce surface area. The controlled atmosphere (oxygen or oxygen-containing gas) during sintering also helps maintain surface characteristics while ensuring complete removal of organic contaminants, resolving the contradiction between surface area preservation and immunogenicity reduction.
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 resulting materials exhibit improved bioresorption and bioactivity, maintaining mechanical stability and promoting bone regeneration without adverse immunogenic responses, with high surface area hydroxyapatite supporting vascularization and low surface area biphasic calcium phosphate facilitating osteoconduction.
Implementation Method 1
The bone material is degreased
Implementation Method 2
deproteinization, and controlled sintering
Implementation Method 3
oxidising the bone material
Implementation Method 4
sintering the bone material
Implementation Method 5
controlled sintering
Data Source
AI summary
The invention provides a bone material having a specific surface area of at least 80 m2/g and a protein content of less than 1800 ppm.