Preparation Of Hydroxy Zinc Phosphate Hollow Nanopaticles And Their Drug Delivery Properties

Hollow hydroxy zinc phosphate nanoparticles were template-freely synthesised bychemical coprecipitation method and the control of reaction conditions using Zn(NO3)2and (NH4)2HPO4as reactant. The temperature of reaction was controlled under20°C,while the pH value was about8.5. The X-ray diffraction (XRD) analysis revealedthat hydroxy zinc phosphate nanoparticles are the unique crystalline constituent of all thesamples compared with traditional zinc phosphate material. Fourier transform infraredspectrometer (FTIR) showed the existence of hydroxy and phosphate groups in thematerial. The size and morphology of hydroxy zinc phosphate nanoparticles wereinvestigated by scanning electron microscopy (SEM), and transmission electronmicroscopy (TEM). The particles had a size ranging from30to50nm and the hollowones had a wall thickness of about7nm. The analysis of the hollow sturctures werecarried out through nitrogen adsorption and desorption method, which indicated thehollow nanoparticles had an average pore diameter at29.8nm for0°C sample and25.3nm for20°C sample. The Zn/P molar ratio investigated by inductively coupled plasmaemission spectrometer (ICP) was about1.7. The methyl-thiotetrazole (MTT) assayproved hydroxy zinc phosphate nanoparticles had low cell cytotoxicity. Furthermore,anticancer drug (doxorubicin) as a model is used to evaluate the entrapment efficiencyand drug loading capacity of hydroxy zinc phosphate nanoparticles, which showed highloading capacity (>16wt%) for doxorubicin. The laser scanning confocal microscope(LSCM) observations show that the drug can be effectively delivered into cells.