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 (Ti6Al4V 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.

Cytocompatibility assessment of Ti-Zr-Pd-Si-(Nb) alloys with low Young's modulus, increased hardness, and enhanced osteoblast differentiation for biomedical applications.

Ti-based alloys have increased importance for biomedical applications due to their excellent properties. In particular, the two recently developed TiZrPdSi(Nb) alloys, with a predominant ß-Ti phase microstructure, have good mechanical properties, such as a relatively low Young's modulus and high hardness. In the present work, the cytocompatibility of these alloys was assessed using human osteoblast-like Saos-2 cells. Cells grown on the alloys showed larger spreading areas (more than twice) and higher vinculin content (nearly 40% increment) when compared with cells grown on glass control surfaces, indicating a better cell adhesion. Moreover, cell proliferation was 18% higher for cells growing on both alloys than for cells growing on glass and polystyrene control surfaces. Osteogenic differentiation was evaluated by quantifying the expression of four osteogenic genes (osteonectin, osteocalcin, osteopontin, and bone sialoprotein), the presence of three osteogenic proteins (alkaline phosphatase, collagen I, and osteocalcin) and the activity of alkaline phosphatase at different time-points. The results demonstrated that TiZrPdSi and TiZrPdSiNb alloys enhance osteoblast differentiation, and that cells grown on TiZrPdSiNb alloy present higher levels of some late osteogenic markers during the first week in culture. These results suggest that the TiZrPdSi(Nb) alloys can be considered as excellent candidates for orthopaedical uses. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 834-842, 2018.