Nanosized Calcium Phosphate Coatings via Bifunctional Precursors
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Solution Overview
Problem
Current methods for producing nanosized calcium phosphate particles, such as hydroxyapatite, face challenges in achieving high specific surface areas and efficient large-scale synthesis, with surfactant-mediated techniques having low yields and requiring extensive purification, and existing coating methods like plasma spray and sol-gel techniques being unsuitable for retaining surface structure or requiring high temperatures.
Innovation Solution
The use of bifunctional precursors with water-soluble organic compounds having multiple functional groups to control crystal growth and attachment to surfaces, allowing for the production of nanosized calcium phosphate particles or coatings with tailored properties, including electrostatic attachment and low-temperature processing to preserve particle size and surface area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If aqueous precipitation method with ammonium hydroxide is used, then calcium phosphate particles are produced, but particle size increases and specific surface area decreases
Solution Approach 1:
The patent uses amino acids as intermediary molecules that adsorb to the crystal surface during precipitation, acting as a mediator between the calcium phosphate nuclei and the growth environment. This intermediary layer prevents excessive crystal growth and agglomeration, maintaining nanosized particles with high specific surface area while enabling controlled synthesis
Solution Approach 2:
The patent changes the chemical parameters of the precipitation system by introducing amino acids with specific functional groups that interact with calcium and phosphate ions. This parameter change modifies the crystallization kinetics and thermodynamics, allowing production of nanosized particles with controlled morphology and high surface area
2Manufacturing precision
If surfactant-mediated techniques are used, then nanosized particles are produced, but yield is low and purification is extensive
Solution Approach 1:
The patent replaces expensive and difficult-to-remove surfactants with inexpensive amino acids that can be easily removed through simple washing or decomposition. The amino acids serve as temporary, disposable agents during synthesis that do not require extensive purification steps, significantly improving synthesis efficiency and productivity
Solution Approach 2:
The amino acids used in the patent can decompose under mild heating conditions to leave clean calcium phosphate surfaces without requiring additional purification agents or steps. This self-service property eliminates the need for extensive purification processes while maintaining nanosized particle morphology
3Ease of manufacture
If plasma spray technique is used, then coating is applied, but high temperature damages surface structure
Solution Approach 1:
The patent replaces the high-temperature plasma spray mechanical/thermal system with a chemical solution-based coating method. The calcium phosphate coating is applied through chemical precipitation or adsorption from aqueous solutions containing calcium and phosphate ions, eliminating the need for high-temperature processing and preserving the underlying surface structure
4Ease of manufacture
If sol-gel technique is used, then coating is applied, but high temperature or long exposure time is required
Solution Approach 1:
The patent changes the chemical parameters of the coating process by using amino acid-mediated precipitation that proceeds rapidly at ambient or mild temperatures. This parameter change eliminates the need for high-temperature calcination or prolonged drying times required by sol-gel techniques, significantly reducing processing time while maintaining coating quality
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
This method enables the production of nanosized calcium phosphate particles with high specific surface areas and efficient coating on various surfaces, including sensitive materials like titanium, while maintaining small particle size and bioactivity, overcoming the limitations of existing techniques.
Implementation Method 1
Additives can adsorb to the crystal surface and prevent dissolution of small crystals, and also shield the crystals from colliding.
Implementation Method 2
The positively charged groups of the organic compounds coating the calcium phosphate particles attach electrostatically to the solid support
Implementation Method 3
removing the organic compounds by heating at a temperature in the range of 250°C - 600 °C
Data Source
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AI summary
Method of producing calcium phosphate particles, such as hydroxyapatite particles, in the form of a powder or coating on a solid support comprising an oxide surface or a polymer surface, such as titanium, titanium alloys, stainless steel, zirconia, glass and poly(styrene), poly(ether ether ketone) (PEEK), and poly(imide) is described. The method comprises I) providing a water solution containing calcium ions and water-soluble organic compound(s) comprising at least two functional groups, II) providing another water solution containing phosphate ions and water-soluble organic compound(s) comprising at least two functional groups, followed by III) mixing the solutions of (I) and (II) to create calcium phosphate particles coated with said water-soluble organic compounds. After washing and drying, the coated particles may be used as scaffolds or for production of a powder of calcium phosphate particles or crystals.