Antibacterial Activity and Cytotoxicity of Silver Chloride/Silver Nanocomposite Synthesized by a Bacterium Isolated from Antarctic Soil

Abstract

This study aims to describe the antibacterial and cytotoxic properties of a nanocomposite composed of silver chloride and silver nanoparticles (AgCl/Ag) biogenically synthesized using Arthrobacter sp., a non-pathogenic Antarctic soil bacterium. Spherical nanoparticles (hydrodynamic size of 42 nm) coated with biomolecules derived from Arthrobacter sp. were obtained. The antibacterial activity of the nanocomposite was demonstrated against Gram-positive and Gram-negative bacterial strains, including the multidrug-resistant Pseudomonas aeruginosa KPC 37. Furthermore, the cytotoxicity of AgCl/Ag nanocomposite was evaluated against the non-tumoral (Vero) and tumoral (SW-1353) cell lines. The nanocomposite was not cytotoxic to the Vero cells at concentrations below 150 μg/mL, whereas at concentrations above 25 μg/mL, a significant cytotoxic effect was observed for the SW-1353 cells. Interestingly, at 150 μg/mL, the nanocomposite demonstrated a potent antibacterial activity for all bacterial strains evaluated. To the best of our knowledge, this is the first report describing the green synthesis of AgCl/Ag nanocomposite by the bacterium Arthrobacter sp. isolated from Antarctic soil. The obtained nanocomposite may find important biomedical applications, with potent antibacterial and antitumoral effects and low toxicity to healthy cells.