In vitro study of the SBF and osteoblast-like cells on hydroxyapatite/chitosan-silica nanocomposite

Hydroxyapatite/chitosan-silica (HApCSi) nanocomposites were synthesized by co-precipitated method and their potential application as filler materials for bone regeneration were investigated in simulated body fluid (SBF). To study their biocompatibility, they were cultured with rat osteoblast-like UMR-106 cells for 3, 7, 14, and 21 days. Studies of the silica contents in chitosan matrix showed the presence of silinol (Si-OH) groups in CSi hybrid and their decrease after being composited with calcium phosphate (CaP) which is desirable for the formation of the apatite. XRD and TEM studies showed that the HAp formed in the CSi matrix were nanometer (20-40 nm) in size. Nanocomposites of HApCSi20 processed with 20%v/v silica whisker showed a micro hardness of 84.7 ± 3.3 MPa. Mineralization study in SBF showed the formation of apatite crystals on the HApCSi surface after being incubated for 7 days. In vitro biocompatibility, cell morphology, proliferation, and cell adhesion tests confirmed the osteoblast attachment and growth on the HApCSi20 surface. The density of cells and the production of calcium nodules on the substrate were seen to increase with increasing cultured time. The mechanical evaluation and in vitro experiment suggested that the use of HApCSi composite will lead to the formation of new apatite particles and thus be a potential implant material.