In-vitro cell adhesion and proliferation of adipose derived stem cell on hydroxyapatite composite surfaces.

The goal of this work was to enhance the mechanical strength and fracture toughness of brittle hydroxyapatite (HAP) by reinforcing it with nanocomposites such as graphene oxide (GO), carbon nanotubes (CNT) and Titania. The goal was also to evaluate the cytotoxicity and the cellular adhesion/proliferation of these composites. The composites were characterized for their crystallinity, functionality, morphology and mechanical properties. Altering the composition by adding 1wt% GO and CNT significantly altered the wettability, hardness and roughness. Further, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FITR) and X-ray photoelectron spectroscopy (XPS) results confirm the crystal structure, bulk chemical composition and surface elemental composition respectively of the composites. The bulk hardness of HAP with CNT was significantly higher than that of HAP. The wettability of HAP with GO was significantly lower than that of HAP with GO and Titania. Adipose Derived Stem Cells (ADSCs) were used for this study to evaluate cytotoxicity and viability. HAP with CNT and HAP with CNT and Titania were found to be least cytotoxic compared to other composites as evaluated by Lactate Dehydrogenase (LDH) assay and alamarBlue assay. ADSC adhesion and proliferation was investigated after 1, 4 and 7days of culture using fluorescence microscopy. All the composites nurtured ADSC adhesion and proliferation, however, distinct morphological changes were observed by using Scanning Electron Microscopy (SEM). Overall, these composites have the potential to be used as bone graft substitutes.