Does Biosynthetic Silver Nanoparticles Are More Stable With Lower Toxicity than Their Synthetic Counterparts?

Control of size and shape is a challenge in nanoparticle synthesis. Synthetic and biosynthetic (both extracellular and intracellular) methods are used to prepare silver nanoparticle (SNP). In this study, the behavior of three strains of Staphylococcus aureus (S. aureus) was investigated in the presence of silver nitrate intra- and extracellularly. S. aureus strains biosynthesized SNPs intracellularly, while in the method of the extracellular biosynthesis, none of the strains could produce the SNP under different conditions (dark, bright light, and the presence of nitrate ion). Intracellular SNPs were purified. The results of this study and previous results were used to compare different properties of the biosynthetic (intra- and extracellular) and synthetic SNPs in terms of shape, size, zeta potential, stability, and toxicity. The results confirmed lower toxicity of biosynthetic SNPs in-vitro assays, and their more stability with less aggregation compared to the synthetic ones. Also, the biosynthetic nanoparticles were found uniform and small. These nanoparticles may be useful for being employed as biosensors.