Design And Preparation Of Mesoporous Hydroxyapatite Nanoparticles And Preliminary Study Of The Synthesis Mechanism

Hydroxyapatite （Ca10（PO4）6（OH）2, HAP） has been considered as the mostnotable of the calcium phosphate. Having the similar composition and crystalstructure as Human bone, HAP has excellent osteoconductive and bioactiveproperties, which could induce bone formation on its surface and form strongbiological fixation. Mesoporous hydroxyapatite also possesses some uniqueadvantages, such highly ordered mesostructures, adjustable pore diameter, highsurface areas. Owing to those structural properties, it is beneficial to separate,adsorb, catalyze, transfer and release gene（drug）. To achieve optimizedperformances in the applications, many strategies have been developed tosynthesize HAP with controlled morphologies and architectures. Among them,mesoporous HAP with spherical morphology is considered to be the idealcandidate. However, up to now, most of the particles are rod-shaped and thedegree of pore ordering are lower used traditional method. And its mechanismwere studied.Herein, the mesoporous hydroxyapatite nanoparticles was described in thispaper with two preparation methods. The first method was hydrothermalsynthesis using ammonia as the catalyst under the room temperature condition.The second way of preparing mesoporous hydroxyapatite was established withcombined sol-gel technology with homogeneous deposition, which was aninnovative approach with the urea as catalyst. The products prepared by the twomethods were characterized by XRD diffraction, scanning electron microscopy,Fourier Transform Infrared Spectroscopy. Furthermore, the influence factors to the size and pore structure of product were investigated, such as calcinations,aged temperature, time, and so on. The results show that the producst prepared byhydrothermal method are bulk, and larger than the products prepared using asol-gel with homogeneous precipitation. The particles with our way are sphericalshape and has a pore structure. The optimum reaction conditions as following: theorder of sequential dropwise is CTAB-P-Ca, and the molar ratio is urea: CTAB:CaCl₂: Na3PO4=18.3:0.24:1.67:1.