Synthesis, characterization and kinetic study of silver and gold nanoparticles produced by the archaeonHaloferax volcanii

Aims To evaluate the ability of the haloarchaeonHaloferax volcaniito produce Ag and Au nanoparticles (NPs) and to characterize the obtained material in order to find relevant properties for future potential applications. Methods and Results Nanoparticles were produced by incubatingH. volcaniicells with the corresponding metal salt. In the presence of precursor salts, cultures evidenced a colour change associated to the formation of metallic nanostructures with plasmonic bands located in the visible range of the spectrum. X-ray fluorescence analysis confirmed the presence of Ag and Au in the NPs which were spherical, with average sizes of 25 nmol l(-1)(Ag) and 10 nmol l(-1)(Au), as determined by electronic microscopy. Fourier transformed infrared spectroscopy indicated that both types of NPs showed a stable protein capping. Ag NPs evidenced antibacterial activity and Au NPs improved the specificity of polymerase chain reaction reactions. Au and Ag NPs were able to reduce 4-nitrophenol when incubated with NaBH4. Conclusions Haloferax volcaniiis able to synthesize metallic NPs with interesting properties for technological applications. Significance and Impact of the Study Our data demonstrate the ability ofH. volcaniito synthesize metal NPs and constitutes a solid starting point to deepen the study and explore novel applications.