Synthesis and Biological Properties of Silver Chloride Nanoparticles Using Cell-free Extracts of Aeromonas ‎hydrophila and Antibacterial Activity against Drug-Resistant Bacteria

HIGHLIGHTS

Evaluation of a new method for preparing bacterial cell-free extract to develop a simple, cost-effective, biocompatible and environmental approach

NADH-dependent nitrate reductase enzyme is present as the most important factor for silver ion reduction and silver nanoparticle production.

There is a significant difference between the antioxidant activity of nanoparticles compared to the extract.

Biosynthesized nanoparticles have a stronger antibacterial potential than drug-resistant bacteria.

Biosynthesized nanoparticles have cytotoxic effects in some human cell lines (breast cell line (MCF-7) and liver cancer (HepG-2).

Abstract

Microorganisms have been studied as potential biological factories for the synthesis of silver nanoparticles. In the present study, the cell-free extract of Aeromonas ‎hydrophila was used to synthesize silver nanoparticles because the extract has a dual role in reducing and stabilizing silver nanoparticles. In this study, silver nanoparticles were synthesized using Aeromonas hydrophila. Synthetic nanoparticles were examined using ultraviolet-visible spectroscopy, X-ray diffraction, Fourier transform infrared (FT-IR), transmission electron microscopy (TEM) and X-ray diffraction (EDX) spectroscopy. In this study, antimicrobial properties of Staphylococcus aureus, Bacillus subtilis, Escherichia coli and Pseudomonas aeruginosa and anti-cancer properties (MCF-7, HepG-2) of silver nanoparticles were investigated. The synthesis of silver nanoparticles was confirmed by ultraviolet-visible spectroscopy and X-ray diffraction. TEM images detected the spherical shape of nanoparticles of various sizes in the range of 1-20 nm. FT-IR analysis demonstrated that enzyme, protein and carbohydrate compounds can be proven as stabilizing agents on the surface of silver nanoparticles. The resulting nanoparticles had strong antibacterial activity against drug-resistant bacteria. Silver chloride nanoparticles were also toxic to MCF-7 and HepG-2 cancer cells. The green synthesis method is cost-effective, environmentally friendly and an easy alternative to conventional silver nanoparticle synthesis methods.

Keywords:
Silver nanoparticles; green synthesis; Aeromonas ‎hydrophila; antimicrobial activity