Green Synthesis of Gold Nanoparticles Coupled with Nucleic Acid Oxidation

Abstract

Green synthesis of metal nanoparticles, especially gold nanoparticles (AuNPs), has attracted the great interest of scientists and engineers in the medical and pharmaceutical fields; thus, a variety of ecofriendly, energy-and cost-saving techniques have been developed. In this study, we found that cells of Leptothrix (iron-oxidizing bacteria) released extracellular RNA some of which could exist as a constituent of the cell-enclosing sheaths. As a part of studies of metal encrustation in the sheaths, here we show that RNA prepared from the Leptothrix cells can reduce Au(III) and spherical AuNPs eventually form when an aqueous HAuCl 4 solution is added under ambient conditions. RNA and DNA of other organismal origins have the same ability. Of the nucleosides and nucleobases, only guanosine and guanine can form AuNPs. The DNA moiety, 2′-deoxyguanosine (dG) (used as a reference material), forms AuNPs when mixed with HAuCl 4 solution, but 8-hydroxy-2′-deoxyguanosine (8-OHdG) does not, indicating that AuNP formation evidently depends on the reduction potential of the guanine moiety, not the sugar moiety. This finding is the first demonstration that spherical AuNPs of ca. 5 nm diameter can be obtained by simply adding guanine to HAuCl 4 solution at ambient temperature; no other chemicals or physical treatments are needed.

Synthesis and characterization of gold nanoparticles from aqueous leaf extract of Alternanthera sessilis and its anticancer activity on cervical cancer cells (HeLa)

“…Green synthesis of AuNPs is an economic and environmental-friendly approach. These nanoparticles could provide an active coating of biological residues on the surface of the particle and also avoid the usage of chemicals [23]. Therefore, we used green synthesis AuNPs from Alternanthera sessilis leaf extract and it was characterized by UV-visible spectroscopy, EDX spectroscopy, SAED, FTIR, HR-TEM and atomic force microscopy.…”

Successful Green Synthesis of Gold Nanoparticles using a Corchorus olitorius Extract and Their Antiproliferative Effect in Cancer Cells

“…Moreover, this methodology improves the biocompatibility of the obtained NPs [ 9 , 10 , 11 ]. For instance, many successful attempts have been reported in the literature, which achieve the synthesis of nanoparticles using biological systems, such as yeast, fungi, and bacteria [ 9 , 10 , 11 , 12 ].…”

Green synthesis of Nerium oleander-conjugated gold nanoparticles and study of its in vitro anticancer activity on MCF-7 cell lines and catalytic activity

“…Colloidal AuNPs stabilized with phytochemicals in aqueous medium are required for many of its applications. In a bottom-up synthetic strategy, plant and fungi extract mediated solution phase synthesis of AuNPs involving reduction of Au(III) to Au(0) has gained profound significance in recent years because of the renewable and biocompatible nature of the plant and fungi extracts, eco-friendly aqueous medium and mild reaction condition [ 16 – 18 ]. Additional advantage of this method is that the extract itself acts as a stabilizer and no additional stabilizers are required.…”