Preparation of Mesoporous Nano-Hydroxyapatite Using a Surfactant Template Method for Protein Delivery

Abstract

Mesoporous nano-hydroxyapatite (n-HA) has gained more and more attention as drug storage and release hosts. The aim of this study is to observe the effect of the ratio of surfactant to the theoretical yield of HA on the mesoporous n-HA, then to reveal the effect of the mesoporous nanostructure on protein delivery. The mesoporous n-HA was synthesized using the wet precipitation in the presence of cetyltrimethylammonium bromide (CTAB) at ambient temperature and normal atmospheric pressure. The morphology, size, crystalline phase, chemical composition and textural characteristics of the product were well characterized by X-ray Powder Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Dynamic Light Scattering (DLS) and N2 adsorption/desorption, respectively. The protein adsorption/release studies were also carried out by using Bovine Serum Albumin (BSA) as a model protein. The results reveal that the mesoporous n-HA synthesized with CTAB exhibits high pure phase, low crystallinity and the typical characteristics of the mesostructure. The BSA loading increases with the specific surface area and the pore volume of n-HA, and the release rates of BSA are different due to their different pore sizes and pore structures. n-HA synthesized with 0.5% CTAB has the highest BSA loading and the slowest release rate because of its highest surface area and smaller pore size. These mesoporous n-HA materials demonstrate a potential application in the field of protein delivery due to their bioactive, biocompatible and mesoporous properties.