An in situ synthesis of mesoporous SBA-16/hydroxyapatite for ciprofloxacin release: in vitro stability and cytocompatibility studies

The present work developed a biomaterial (HA/SBA-16) based on the growth of calcium phosphate (HA) particles within an organized silica structure (SBA-16) to evaluate its application as a drug delivery system. The samples were charged with ciprofloxacin as a model drug and in vitro release assays were carried out. The samples were characterized by elemental analysis (CHN), Fourier transform infrared spectroscopy, nitrogen adsorption, scanning electron microscopy (SEM), transmission electron microscopy (TEM), small angle X-ray scattering (SAXS) and X-ray diffraction. The results obtained by TEM, SEM and SAXS reveal a well-defined cubic arrangement of a uniform spherical mesoporous structure, an intrinsic characteristic of these materials, which indicated that SBA-16 and HA/SBA-16 could potentially encapsulate bioactive molecules by means of ordered mesopores. It was found that both surface interaction and pore volume affect the rate and amount of ciprofloxacin released from the mesoporous materials. In vitro assays were performed to evaluate the adhesion, viability, and growth behavior of human adipose tissue-derived stem cells (hADSC) on SBA-16 and HA/SBA-16 nanocomposites to verify their potential as a scaffold for application in bone-tissue engineering using MTT assay and alkaline phosphatase activity tests. The results showed that the materials are promising systems for bone repair, providing a good environment for the adhesion and proliferation of rat mesenchymal stem cells and hADSC in vitro.