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TiO 2 nanotubes were grafted on the surface of cpTi, Ti6Al4V and Ti6Al4V-ELI with the aim to provide a new podium for human pre-osteoblast cell (MC3T3) adhesion and proliferation. The surface morphology and chemistry of these alloys were examined with scanning electron microscopy and energy dispersive x-ray spectroscopy. TiO 2 nanotubes were further characterized by cyclic potentiodynamic polarization tests and electrochemical impedance spectroscopy. The vertically aligned nanotubes were subjected to pre-osteoblast cell proliferation in order to better understand cell–material interaction. The study demonstrated that these cells interact differently with nanotubes of different titanium alloys. The significant acceleration in the growth rate of pre-osteoblast cell adhesion and proliferation is also witnessed. Additionally, the cytotoxicity of the leached metal ions was evaluated by using a tetrazolium-based bio-assay, MTS. Each group of data was operated for p < 0.05, concluded one way ANOVA to investigate the significance difference. [ABSTRACT FROM AUTHOR]

In the realm of biomaterials, metallic materials are widely used for load bearing joints due to their superior mechanical properties. Despite the necessity for long term metallic implants, there are limitations to their prolonged use. Naturally, oxides of titanium have low solubilities and form passive oxide film spontaneously. However, some inclusion and discontinuity spots in oxide film make implant to adopt the decisive nature. These defects heighten the dissolution of metal ions from the implant surface, which results in diminishing bio-integration of titanium implant. To increase the long-term metallic implant stability, surface modifications of titanium alloys are being carried out. In the present study, biomimetic coatings of plasma sprayed hydroxyapatite and titanium were applied to the surface of commercially pure titanium and Ti6Al4V. Surface morphology and surface chemistry were studied using scanning electron microscopy and X-ray photoelectron spectroscopy, respectively. Cyclic potentiodynamic polarization and electrochemical impedance spectroscopy were carried out in order to study their electrochemical behavior. Moreover, cytotoxicity analysis was conducted for osteoblast cells by performing MTS assay. It is concluded that both hydroxyapatite and titanium coatings enhance corrosion resistance and improve cytocompatibility. [ABSTRACT FROM AUTHOR]

The selective laser melting of Ti6Al4V would induce definite changes in the microstructure that may affect its corrosion properties. Microstructural examination showed the formation of relatively thin beta (β) lamella in selective laser melted (SLM) Ti6Al4V compared to wrought Ti6Al4V. X-ray diffraction analysis (XRD) analysis confirmed the presence of alpha and beta phases in both SLM and wrought Ti6Al4V. However, the higher concentration of the β phase in SLM Ti6Al4V compared to wrought Ti6Al4V was evident in the microstructure. As candidate dental implant materials, the corrosion behavior of both SLM and wrought Ti6Al4V was assessed in artificial saliva (AS) and deionized water (DI) containing various species i.e. fluoride (F), calcium chloride (CaCl 2) and lactic acid (LA). Electrochemical impedance spectroscopy and potentiodynamic polarization analysis was carried out to estimate the corrosion behavior of SLM and wrought Ti6Al4V at room temperature. SLM Ti6Al4V offered better corrosion resistance than wrought Ti6Al4V in all solutions at pH > 6. However, wrought Ti6Al4V comparatively presented high corrosion resistance in AS + LA, DI + CaCl 2 and DI + LA solutions (pH < 6). The lower dissolution rate of SLM Ti6Al4V (at pH > 6) was attributed to larger β content in the microstructure compared to wrought Ti6Al4V. • Corrosion behavior of SLM Ti6Al4V was studied in artificial saliva and deionized water based electrolytes. • Microstructural examination of both SLM and wrought Ti6Al4V was studied. • SLM Ti6Al4V showed higher corrosion resistance in electrolytes with pH above 6. [ABSTRACT FROM AUTHOR]

Abstract The present study focused on the development of magnesium-functionalized graphene oxide (FGO) coating on titanium alloy (Ti6Al4V) by electrophoretic deposition. Graphene oxide (GO) was synthesized by modified Hummers' method and functionalized with magnesium ions. X-ray diffraction, infrared spectroscopy (IR) and Raman spectroscopy were employed to confirm the synthesis of GO and GO-coatings on Ti6Al4V. Functionalization of GO with Mg ions was confirmed by energy dispersive X-ray spectroscopy. The surface morphology of coated samples was examined through scanning electron microscopy. Reduction of FGO coating (labelled as rFGO) by heating at 200 °C was confirmed by IR. The rFGO coated Ti6Al4V was found to be hydrophilic in nature as determined by contact angle measurement which showed reduction in the contact angle of Ti6Al4V from 95.4° to 42.1°. The percent cell viability over the coated sample was appreciably improved compared to as-received Ti6Al4V sample owing to hydrophilicity of the former. The positive shift in open circuit potential and increase in polarization resistance was observed after coating Ti6Al4V samples with FGO. The significant decrease in the corrosion current density and negative polarization loop in the reverse scan of samples also confirmed the improved corrosion resistance of rFGO-coated Ti6Al4V over uncoated Ti6Al4V in the PBS solution. Furthermore, the impedance spectroscopy revealed that the preferential adsorption of ionic species (indicated by large R ads) at the surface improved the barrier characteristics of rFGO coated samples and exhibited an order of magnitude higher R ct compared to as-received samples. Highlights • GO functionalized with Mg was deposited on Ti6Al4V alloy via EPD. • The presence of GO significantly decreased the contact angle of Ti6Al4V alloy. • Adhesion and viability of MC3T3-E1 cells were improved in the presence of coating. • Significant decrease in I corr and higher R p values suggested an improved corrosion resistance. [ABSTRACT FROM AUTHOR]

The constant demand for new implant materials and the multidisciplinary design approaches for stent applications have expanded vastly over the past decade. The biocompatibility of these implant materials is a function of their surface characteristics such as morphology, surface chemistry, roughness, surface charge and wettability. These surface characteristics can directly influence the material's corrosion resistance and biological processes such as endothelialization. Surface morphology affects the thermodynamic stability of passivating oxides, which renders corrosion resistance to passivating alloys. Magnetoelectropolishing (MEP) is known to alter the morphology and composition of surface films, which assist in improving corrosion resistance of Nitinol alloys. This work aims at analyzing the surface characteristics of MEP Nitinol alloys by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The wettability of the alloys was determined by contact angle measurements and the mechanical properties were assessed by Nanoindentation. Improved mechanical properties were observed with the addition of alloying elements. Cyclic potentiodynamic polarization tests were performed to determine the corrosion susceptibility. Further, the alloys were tested for their cytotoxicity and cellular growth with endothelial cells. Improved corrosion resistance and cellular viability were observed with MEP surface treated alloys. [ABSTRACT FROM AUTHOR]

Magnesium alloys have raised an immense amount of interest to many researchers because of their evolution as a new kind of third generation materials. Due to their biocompatibility, density, and mechanical properties, magnesium alloys are frequently reported as prospective biodegradable implant materials. Moreover, magnesium alloys experience a natural phenomenon to biodegrade in aqueous solutions due to its corrosion activity, which is excellent for orthopedic and cardiovascular applications. However, a major concern with such alloys is fast and non-uniform corrosion degradation. Controlling the degradation rate in the physiological environment determines the success of biodegradable implants. In this investigation, three different grades of magnesium alloys: AZ31B, AZ91E and ZK60A were studied for their corrosion resistance and biocompatibility. Scanning electron microscopy, energy dispersive spectroscopy, atomic force microscopy and contact angle meter are used to study surface morphology, chemistry, roughness and wettability, respectively. Additionally, the cytotoxicity of the leached metal ions was evaluated by using a tetrazolium based bio-assay, MTS. [ABSTRACT FROM AUTHOR]