Cytocompatibility assessment of Ti-Nb-Zr-Si thin film metallic glasses with enhanced osteoblast differentiation for biomedical applications

Biologically safe Ti-based quaternary Ti-Nb-Zr-Si thin film metallic glass (TFMG) was fabricated by sputtering on Titanium alloy (Ti6A14V or Ti alloy) substrates. A preliminary assessment regarding glass forming ability, thermal stability and corrosion behavior was performed. The amorphous nature of the film is evidenced from the X-ray Diffraction (XRD) and Transmission Electron Microscope (TEM) and Selected Area Electron Diffraction (SAED) patterns. Ion scattering spectroscopy (ISS) and X-ray Photoelectron Spectroscopy (XPS) were used to analyse the chemical composition of surface which indicated oxygen on the top surface of the film and confirms the presence of Ti, Nb, Si, Zr without any other impurities. The surface morphology of the film showed a smooth surface as observed from scanning electron microscope (SEM) and atomic force microscope (AFM) analysis. It is found that the TFMG can sustain in the body-fluid, exhibiting superior corrosion resistance and electrochemical stability than the bare titanium. The cytotoxicity studies with L929 fibroblast cells showed that coatings were graded as zero and non-cytotoxic in nature. No hemolysis was observed on the coated surface indicating a better hemocompatibility. Assay using SaOS-2 bone cells showed good growth on the coated surfaces. The calcium assay showed that the SaOS-2 cells grown and differentiated on the control (Tissue Culture Polystyrene) TCPS surface had the highest mineral level. Higher alkaline phosphatase activity is obtained in SaOS-2 osteoblast cell cultures on TFMG than the control.