Simple green production of silver nanoparticles facilitated by bacterial genomic DNA and their antibacterial activity

Abstract

Green synthesis of AgNPs has gained many research interests as a low cost and eco-friendly approach. This work reported on the use of bacterial genomic DNA as the alternative biopolymer for a green production of AgNPs under a neutral pH. Although both ssDNA and dsDNA could function as stabilizing agents during the synthesis process, the ssDNA, generated by pre-heating the dsDNA at 100 °C, was more efficient to produce AgNPs with higher yield as determined by the intensity of the surface plasmon resonance (SPR) peak of silver at 475 nm. The obtained AgNPs were spherical with the average diameter of 15.0 ± 7.6 nm, which their identity was confirmed by X-ray diffraction, high-resolution transmission electron microscopy, and selected area electron diffraction analyses. The synthesized AgNPs exhibited the potent antibacterial activity against both Escherichia coli and Staphylococcus aureus with the minimum bactericidal concentrations at 250 and 500 μg/ml, respectively, suggesting their potential antibacterial activity against both Gram-negative and Gram-positive bacteria.