Synthesis And Application Of Hollow Calcium Phosphate Nanoparticles

With the characteristics of large useful inner spaces, high specific surface area, low density and so on, hollow-structured nanospheres have attracted more attentions. Hollow nanospheres are generally synthetized from core-shell composite materials, the properties of the hollow spheres such as optical, thermal, electrical, magnetic and catalytic properties can be controlled by adjusting the structure, size and the composition of the core-shell composite materials. The inner space of the hollow particles can hold more or larger sized guest molecules which can be used as carriers. Hollow nanospheres can play very important role in many areas such as medical, biochemical, chemical engineering and so on.Various methods, such as coaxial nozzle techniques, microemulsion and reverse microemulsion methods, exchange-resin methods, self-organization methods, spray drying method and template method, have been employed to prepare hollow spheres.In this study, a size controllable synthesis of hollow structures of biological apatite in a three-phase system of hexane-water-bis(2-ethylhexyl) sulfosuccinate is demonstrated. By using this method, the sizes of the obtained hollow spheres can be easily regulated within a range of 50-1000 nm and the thickness of their shells is about 15 nm. Niosomes are non-ionic surfactant vesicles obtained on hydration of synthetic nonionic surfactants, with or without incorporation of cholesterol or other lipids. They are vesicular systems similar to liposomes that can be used as carriers of amphiphilic and lipophilic drugs. The advantages compared to liposome are more stable, having a determinate composition, easy to storage, low cost, no adverse reactions and so on, and noisome has become one of the research focus of novel drug delivery system. In this work, we used the vesicles formed from the self assembly of Tween 80 and poly(ethylene glycol) in aqueous solution in a certain molar radio as templates to synthetize calcium phosphate nanoparticles and encapsulated bovine serum albumin (BSA) as a model protein. The morphology and structure were evaluated by transmission electron microscope (TEM), scanning electron microscopy (SEM), X-ray diffraction and fourier transform infrared spectroscopy (FTIR). The results show that the calcium phosphate particles were amorphous and the size was in the range of 100-150 nm. The drug-loading content and drug release content were higher compared to the hydroxyapatite particles system.