A Facile chemical route to synthesize Zn doped hydroxyapatite nanorods for protein drug delivery

Porous and hollow hydroxyapatite (HAp) materials are widely used in the field of protein drug delivery. However, few studies have examined the systematic adsorption and sustained release ability of proteins on the one-dimensional HAp. In this work, undoped HAp and a series of zinc (Zn)-containing hydroxyapatite (ZnHAp) were prepared by a simple hydrothermal process as protein drug carriers. The phase analysis, surface functional groups, morphologies and zeta potentials of the samples were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and Nano-ZS Zetasizer. The characterization results were found that the crystal structures and chemical functional groups of ZnHAp were similar to those of HAp. And all samples doped with Zn exhibited a uniform rod-like morphology, while the HAp consisted of nanobelts. When the Zn concentration increased, the particle size and lattice parameter of ZnHAp decreased slightly as well as zeta potential. The protein adsorption and release tests indicated that the prepared ZnHAp had a much higher protein payload and the protein-loading amount of 1ZnHAp reached 115.1 mg/g, which was about 3.786 times that of HAp. Moreover, the ZnHAp had a good protein release ability than HAp, using lysozyme (LYS) as the model drug.