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Microbial-mediated Au@biolayer core-shell nanoparticles: synthesis and application
W.J. Liu, C.Y. Jing
Chinese Academy of Science, CN
Keywords: microorganism, gold, application
Summary:
Gold nanoparticles (Au NPs) bio-synthesized through microbial activities create biocompatible and non-toxic nanomaterials that may have great applications in analysis, catalysis, and biomedicine. Herein, we demonstrated that Pantoea sp. IMH can generate Au@biolayer core-shell nanoparticles. Examination of Pantoea sp. IMH incubated in HAuCl4, using UV-Vis spectroscopy, HRTEM-ED-EDS, XRD, XANES, SEM-EDS, and FTIR, provided complementary identification and characterization. Microbial-mediated Au@biolayer NPs were one-step synthesized core-shell nanoparticles that thin (~3 nm) layer was coated on the spinous Au nanoparticles. This unique composition enables the application of the biogenic Au@biolayer NPs in the removal and detection of dyes using surface enhanced Raman scattering (SERS). Our adsorption experimental results show that the removal efficiency of cationic crystal violet, malachite green, and rhodamine 6G rapidly reached equilibrium within 2 min at 98.3%, 59.2%, and 97.7%, respectively. While the adsorption of congo red was only 3.6% because of its anionic property. Similarly, substantial SERS enhancements were observed for these three positively charged dyes. DFT calculation implied that the SERS enhancement may be mainly due to the electromagnetic mechanism. Our results will help to understand the transformation of metal ions to nanoparticles in the natural environment and the gold biosynthesis mechanism.
