Antimicrobial Activity and Degradation of Superhydrophobic Magnesium Substrates in Bacterial Media

Abstract

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.

Development and Application of Biodegradable Metals

“…As seen in the Special Issue "Magnesium Alloys for Biomedical Applications" in 2020 [2], current research on magnesium alloys focuses on Al-free alloys. Accordingly, one paper of this Special Issue is based on a magnesium-manganese alloy [3], one study focuses on magnesium-dysprosium [4], others focus on magnesium-silver [5] or pure magnesium [6], and three papers are based on magnesium-zinc alloys [7][8][9]. This Special Issue shows that alongside alloying and optimizing casting [4] and extrusion parameters, manufacturing based on powder metallurgy [1,7,8], the optimization of surface properties [3,9], techniques to further refine grain size, such as wire drawing [5], and severe plastic deformation techniques, such as equal channel angular pressing (ECAP) and high-pressure torsion (HPT) [6], are key to the improvement of mechanical and corrosion properties.…”

“…The antibacterial potential of magnesium-based materials was studied by Emelyanenko et al [3]. Superhydrophobic coatings on a magnesium-based alloy were fabricated and the behavior in bacterial dispersions of Pseudomonas aeruginosa and Klebsiella pneumoniae cells in phosphate-buffered saline was analyzed.…”

Recent progresses in super-hydrophobicity and micro-texturing for engineering applications

“…The immersion of such SHS into bacterial dispersion followed notable morphological changes due to deposition of corrosion products like formation of covering film, and bundles of rods of magnesium phosphates, potassium and sodium phosphates. The formation of corrosion reactions causes a significant rise in pH and subsequently bacterial cell killing [62].…”

The Effect of Co-Encapsulated GO-Cu Nanofillers on Mechanical Properties, Cell Response, and Antibacterial Activities of Mg-Zn Composite

“…However, the appropriateness of Mg alloys as a fracture fixation system has been questioned because of their low resistance to corrosion and relatively inferior mechanical properties. Different techniques have been utilized to resolve low corrosion resistance and insufficient yield strength of magnesium alloys, including preparation of Mgbased metal matrix composites (MMCs) using suitable bioactive reinforcements, which is steadily gaining interest [15][16][17][18]. Incorporating bio-metallic or bio-ceramic reinforcements to magnesium-based alloys to fabricate composites can improve biocompatibility, corrosion resistance, and mechanical properties.…”