Synthesis Of Biocompatible Hollow Nanostructured Materials And Their Applications In Drug Delivery

Biocompatible hollow nanostructured materials have great potentialapplications in biomedicine due to their excellent biocompatibility, special cavitiesand porous structures. In this dissertation, a variety of nanostructured HA hollowspheres/tubes and nanostructured CaCO₃hollow spheres have been prepared bydifferent chemical methods. The drug loading and release behaviors of them havebeen studied. The main points are summarized as follows:1．Uniform HA hollow nanospheres have been synthesized via a solvothermalmethod in mixed solvents of water and glycerin with CO2bubble as soft templatesand CaCl₂,（NH₄）₂HPO₄as reactants. The HA hollow spheres with averagediameters of about500nm and shell thicknesses of about100nm are actuallycomposed of nanosheets with thickness of about10nm. Through tuning the volumeratio of glycerin/water, HA hollow and solid spheres with controllable morphologyand size can also be prepared. We have further investigated their ibuprofen （IBU）loading and release behaviors in controlled drug release system. According to theexperimental results, the nanostructured HA hollow spheres exhibit higher drugloading capacity and more favorable release property than those nanostructured HAsolid spheres.2.Various CaCO₃hollow spheres have been successfully synthesized by usingCaCl₂and (（NH₄）₂CO₃as reactants and different surfactants as templates in aqueoussolution at room temperature. We get uniform CaCO₃hollow spheres withdiameters of2-3μm in the presence of SDS, CaCO₃porous vesicles with diametersof1-4μm in the presence of PVP and uniform CaCO₃porous microspheres withdiameters of about1μm in the presence of SDBS. Based on the experimentalresults, the possible formation mechanisms and affecting factors have beenproposed. Simultaneously, the drug loading and release behaviors of CaCO₃hollowspheres/capsules have also been discussed.3.Two kinds of CaCO₃rods have been prepared through tuning the volumeratio of ethanediol/water in mixed solvents of water and ethanediol with CaCl₂andurea as reactants. One with a diameter of around3μm and a length of about20-30μm and the other with an average diameter of around8μm and a length of about 100μm. CaCO₃solid spheres with an average diameter of3μm have also beensynthesized by using CaCl₂and (（NH₄）₂CO₃as reactants in aqueous solution at roomtemperature in the presence of surfactant. Secondly, HA/CaCO₃heterostructuresare prepared from the reaction of the as-prepared CaCO₃rods and solid sphereswith Na2HPO4aqueous solution. Thirdly, by the subsequent treatment ofHA/CaCO₃heterostructures with dilute acetic acid solution, the unreacted CaCO₃are dissolved and HA tubes and hollow spheres are obtained, respectively. Usingmorphology-controllable CaCO₃as template provides a new approach to thepreparation of diverse HA hollow structures.