In vitro and preliminary in vivo toxicity screening of high-surface-area TiO2-chondroitin-4-sulfate nanocomposites for bone regeneration application.

The goal of this study was to prepare nontoxic, biomimetic TiO2/chondroitin-4-sulfate nanocomposites with osteointegration ability for biomedical applications. Nanocomposites with higher surface area were subjected to bioactivity study and obtained bone-like layer with stoichiometric Ca/P ratio of 1.64 and 1.66. The susceptibility of nanocomposites against Staphylococcus aureus (∼16 mm) and Escherichia coli (∼12 mm) is favorable in preventing the risk of bone diseases and postoperative infections. Adequate swelling and degradations properties were favorably achieved to reduce the risk of nanoparticle accumulation in cell organelles. Moreover, the toxicity in AGS cell line and biocompatibility in osteoblast-like MG-63 cell line showed no significant mitochondrial damage. In addition, the in vitro expression of osteoblast inducing genes (OCN, OPN, ALP and COL 1) and their up-regulation, and 20% of increased hatching rate in preliminary in vivo (zebrafish) analysis were favorable for the nanocomposite at the ratio of 2:0.50 than pure TiO2. Hence, it can be concluded that among the prepared nanocomposites TCs.5 is a promising biomimetic biomaterial that can be used for advanced orthopedic research and other applications.