LAUSR

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. Graphical Abstract .