In this study, we applied the method of nanosecond laser treatment for the fabrication of superhydrophobic and superhydrophilic magnesium-based surfaces with hierarchical roughness when the surface microrelief is evenly decorated by MgO nanoparticles. The comparative to the bare sample behavior of such surfaces with extreme wettability in contact with dispersions of bacteria cells Pseudomonas aeruginosa and Klebsiella pneumoniae in phosphate buffered saline (PBS) was studied. To characterize the bactericidal activity of magnesium samples with different wettability immersed into a bacterial dispersion, we determined the time variation of the planktonic bacterial titer in the dispersion. To explore the anti-bacterial mechanisms of the magnesium substrates, a set of experimental studies on the evolution of the magnesium ion concentration in liquid, pH of the dispersion medium, surface morphology, composition, and wettability was performed. The obtained data made it possible to reveal two mechanisms that, in combination, play a key role in the bacterial decontamination of the liquid. These are the alkalization of the dispersion medium and the collection of bacterial cells by microrods growing on the surface as a result of the interaction of magnesium with the components of the buffer solution.
The interest in magnesium-based materials is promoted by their biocompatibility, their bioresorbability, and their recently discovered antibacterial potential. Until now, the widespread use of magnesium alloys in different corrosive environments was inhibited by their weakly controllable degradation rate and poorly understood microbiologically induced corrosion behavior. To better understand the degradation and usability of magnesium-based alloys, in this study we have fabricated superhydrophobic coatings on a magnesium-based alloy, and analyzed the behavior of this alloy in bacterial dispersions of Pseudomonas aeruginosa and Klebsiella pneumoniae cells in phosphate-buffered saline. It was shown that the immersion of such coatings in bacterial dispersions causes notable changes in the morphology of the samples, dependent on the bacterial dispersion composition and the type of bacterial strain. The interaction of the superhydrophobic coatings with the bacterial dispersion caused the formation of biofilms and sodium polyphosphate films, which provided enhanced barrier properties in magnesium dissolution and hence in dispersion medium alkalization, eventually leading to the inhibition of magnesium substrate degradation. The electrochemical data obtained for superhydrophobic samples in continuous contact with corrosive bacterial dispersions for 48 h indicated a high level of anticorrosion protection.
A new group of P*-chiral bisdiamidophosphites has been developed for Pd- and Rh-catalyzed asymmetric reactions with good to excellent enantioselectivities.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.