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The corrosion behavior and cell adhesion property of nanostructured TiO2 films deposited electrolytically on Ti6Al4V were examined in the present in vitro study. The nanostructured TiO2 film deposition on Ti6Al4V was achieved via peroxoprecursors. SEM micrographs exhibit the formation of amorphous and crystallite TiO2 nanoparticles on Ti6Al4V before and after being annealed at 500 degrees C. Corrosion behavior of TiO2-deposited and uncoated Ti6Al4V was evaluated in freely aerated Hank's solution at 37 degrees C by the measurement and analysis of open-circuit potential variation with time, Tafel plots, and electrochemical impedance spectroscopy. The electrochemical results indicated that nano-TiO2 coated Ti6Al4V showed a better corrosion resistance in simulated biofluid than uncoated Ti6Al4V. Rat bone cells and human aortic smooth muscle cells were grown on these substrates to study the cellular responses in vitro. The SEM images revealed enhanced cell adhesion, cell spreading, and proliferation on nano-TiO2 coated Ti6Al4V compared to those grown on uncoated substrates for both cell lines. These results suggested that nanotopography produced by deposition of nanostructured TiO2 onto Ti alloy surfaces might enhance corrosion resistance, biocompatibility, and cell integration for implants made of Ti alloys.

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Electrospun fibers with an average fiber diameter in the nanometer range were prepared from soy protein isolate to develop scaffolds for tissue engineering applications. Poly(ethylene oxide) was added to facilitate fiber formation. The influence of processing parameters such as applied voltage, soy protein isolate and poly(ethylene oxide) concentrations, and poly(ethylene oxide) molecular weight on electrospun fiber morphology was investigated. Resulting soy protein isolate/poly(ethylene oxide) mats were carbodiimide crosslinked to increase construct robustness. Mechanical properties and in vitro biocompatibility of crosslinked electrospun scaffolds were evaluated. Soy protein isolate/poly(ethylene oxide) fiber diameters ranged between 50 and 270 nm depending on both electrospinning and solution parameters. The Young's modulus for 7% soy protein isolate/3% poly(ethylene oxide) and 12% soy protein isolate/3% poly(ethylene oxide) electrospun scaffolds were 75 and 252 kPa, respectively. Human mesenchymal stem cell studies showed successful cell adhesion and proliferation on the soy protein isolate/poly(ethylene oxide) fibers. The structural and biological properties of these soy protein isolate electrospun scaffolds suggest their potential applications in tissue engineering.

The present study deals with the formation and characterization of Cu−benzotriazole (BTA) nanoparticles, which are relevant to copper surface corrosion and passivation. More specifically, we demonstrated that under oxidizing conditions, the cupric ions diffused out of the copper substrate surface can induce the formation of Cu−BTA nanoparticles. These nanoparticles can subsequently precipitate back to the copper surface or form a cross-link with the copper species on the original surface. Such a precipitation path for the formation of a copper-passivating film may supplement or compete with the direct growth mechanism in which the passivating agent interacts with copper species directly before they diffuse out of the substrate surface.

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