Bactericidal Application and Cytotoxic Activity of Biosynthesized Silver Nanoparticles with an Extract of the Red Seaweed Pterocladiella capillacea on the HepG2 Cell Line

Background: Nano-biotechnology is recognized as offering revolutionary changes in various fields of medicine.Biologically synthesized silver nanoparticles have a wide range of applications. Materials and
Methods: Silvernanoparticles (AgNPs) were biosynthesized with an aqueous extract of Pterocladiella (Pterocladia) capillacea,used as a reducing and stabilizing agent, and characterized using UV-VIS spectroscopy, Fourier Transform Infrared (FT-IR) spectroscopy, transmission electron microscopy (TEM) and energy dispersive analysis (EDX). Thebiosynthesized AgNPs were tested for cytotoxic activity in a human hepatocellular carcinoma (HepG2) cell linecultured in Dulbecco’s modified Eagle medium supplemented with 10% fetal bovine serum, 1% antibiotic andantimycotic solution and 2 mM glutamine. Bacterial susceptibility to AgNPs was assessed with Staphylococcusaureus, Bacillus subtilis [Gram+ve] and Pseudomonas aeruginosa and Escherichia coli [Gram-ve]. The agar welldiffusion technique was adopted to evaluate the bactericidal activity of the biosynthesized AgNPs using Ampicillinand Gentamicin as gram+ve and gram-ve antibacterial standard drugs, respectively.
Results: The biosynthesizedAgNPs were 11.4±3.52 nm in diameter. FT-IR analysis showed that carbonyl groups from the amino acid residuesand proteins could assist in formation and stabilization of AgNPs. The AgNPs showed potent cytotoxic activityagainst the human hepatocellular carcinoma (HepG2) cell line at higher concentrations. The results also showedthat the biosynthesized AgNPs inhibited the entire panel of tested bacteria with a marked specificity towardsBacillus subtillus.
Conclusions: Cytotoxic activity of the biosynthesized AgNPs may be due to the presence ofalkaloids present in the algal extract. Our AgNPs appear more bactericidal against gram-positive bacteria (B.subtillus).