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Abstract
In this paper, a new method of one-pot biosynthesizing of gold nanoparticles (GNPs), using chloroplasts as reductants and stabilizers is reported. The as-prepared GNPs were characterized by ultraviolet visible spectroscopy, transmission electron microscopy, X-ray powder diffraction, and Fourier transform infrared spectroscopy (FTIR). The cytotoxicity of the GNPs was evaluated using the 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method against gastric mucous cell line GES-1 and gastric cancer cell line MGC-803. Rhodamine 6G as a Raman probe was used for investigating surface-enhanced Raman spectroscopy (SERS) enhancement of GNPs. The transmission electron microscopy results indicated that the GNPs were spherical in structure and almost 20 nm in diameter. Ultraviolet visible spectroscopy exhibited an absorption peak at 545 nm. The GNPs exhibited high crystallinity, with the (111) plane as the predominant orientation, clarified by X-ray powder diffraction. In addition, a potential mechanism was proposed to interpret the formation process of GNPs, mainly based on the analysis of FTIR results. The FTIR spectrum confirmed that the GNPs were carried with N–H groups. Toxicological assays of as-prepared GNPs revealed that the green GNPs were nontoxic. SERS analysis revealed that the GNPs without any treatment could substantially enhance the Raman signals of rhodamine 6G. The Raman enhancement factor was calculated to be nearly 1010 orders of magnitude. In conclusion, the GNPs with good biocompatibility and excellent SERS effect were successfully synthesized using chloroplasts. These biogenetic GNPs have great potential for ultrasensitive detection of biomarkers in vitro and in vivo based on SERS.
Acknowledgments
This work is supported by the National Key Basic Research Program (973 Project) (2010CB933901), National 863 Hi-tech Project (2007AA022004), Important National Science and Technology Specific Projects (2009ZX10004-311), National Natural Scientific Fund (No. 20771075 and No. 20803040), Special Project for Nanotechnology from Shanghai (No. 1052nm04100), New Century Excellent Talent of the Ministry of Education of China (NCET-08-0350), and Shanghai Science and Technology Fund (10XD1406100). Supported by Project 2011021031-3 (supported by Natural Science Foundation of Shanxi) and Shanghai Jiao Tong University Innovation Fund for Postgraduates (Z-340-011).
Disclosure
The authors claim no conflicts of interest in this work.