In vitro bioactivity and osteoblast cell viability studies of hydroxyapatite-incorporated silica aerogel

Bioactivity and osteoblastic growth of hydroxyapatite (HA)-incorporated silica aerogels (SA) (HAESA) with different ratio of HA/SiO₂ (0.1, 0.5, 1.0, and 1.3 HA/SiO₂) were investigated. Bioactivity of HAESA was studied by immersing all samples in simulated body fluids (SBF) for 7 and 14 days. The recovered samples were then characterised using Fourier transform infrared spectroscopy, X-ray diffraction, field emission scanning electron microscopy combined with energy dispersive X-ray analyser (FESEM–EDX) and the analysis of phosphate loss in the solution. These samples were also investigated for their effect on cell viability and proliferation abilities against normal human osteoblast cells in vitro after 24 and 48 h of exposure times. The HA/SiO₂ ratio affected its bioactivity in which the bioactivity increased to 0.5 (HAESA-0.5) and declined at higher ratios (1.0 and 1.3). A similar trend was observed for cell viability and proliferation assays. HAESA-0.5 (HA/SiO₂ ratio of 0.5), which possesses the optimal characteristics of SA and HA, resulted in the highest osteoblastic growth due to the synergistic effects between SA and HA. Thus, HAESA-0.5 could be an alternative biomaterial compared to silica- and HA-based biomaterials for bone implant application due to its higher bioactivity in SBF with the improved performance of osteoblast growth.

Hydroxyapatite-incorporated silica aerogel with different weight ratio of HA/SiO₂ (HAESA) was studied for their bioactivity in simulated body fluid and in vitro osteoblastic growth.