Synthesis, radical scavenging, and antimicrobial activities of core–shell Au/Ni microtubes

Abstract

Highly ordered Ni/Au core–shell microtube (MT) arrays with the inner diameters of 110 ± 13 nm and the wall thickness of 118 ± 5 nm were synthesized by a two-step template deposition approach in pores of the track-etched membranes. First, the Au MTs were obtained by electroless plating. On the second stage, Ni MTs were electrochemically deposited inside gold MTs. The dimensions, chemical composition, and crystal structure of the synthesized samples have been analyzed using scanning electron microscopy, energy dispersive analysis as well as X-ray diffraction technique. The in vitro antioxidant activity of synthesized single component and core–shell MTs was evaluated by scavenging of 2.2-diphenyl-1-picrylhydrazyl hydrate (DPPH) radical and the effective rate of inhibition IC50 for DPPH radical was found to be 0.49 for Au/Ni MTs and 3.22 and 2.73 for Ni and Au MTs, respectively. The antibacterial activity was elucidated against the strains such as: Staphylococcus aureus, Bacillus subtilis, Escherichia coli and the yeast-like fungus Candida albicans P. by the agar diffusion method. The core–shell Au/Ni MTs possess the highest activity against the tested Gram-negative bacteria E. Coli (zone of inhibition of 37 ± 1.0 mm). Gram-positive bacteria S. Aureus showed resistance to the Au/Ni MTs; however, single component of Au and Ni MTs showed a pronounced antimicrobial activity as compared to Penicillin G sodium (control).