Coalescence of functional gold and monodisperse silver nanoparticles mediated by black Panax ginseng Meyer root extract

Abstract

A rapid biological synthesis of multifunctional gold nanoparticle (AuNp) and monodisperse silver nanoparticle (AgNp) was achieved by an aqueous extract of black Panax ginseng Meyer root. The physicochemical transformation into black ginseng (BG) greatly enhanced the pharmacological activities of white ginseng and its minor ginsenoside content. The optimal temperature conditions and kinetics of bioreduction were investigated. Formation of BG-AuNps and BG-AgNps was verified by ultraviolet–visible spectrophotometry at 548 and 412 nm, respectively. The biosynthesized BG-AgNps were spherical and monodisperse with narrow distribution, while BG-AuNps were icosahedral-shaped and moderately polydisperse. Synthesized nanoparticles exhibited long-term stability in buffers of pH 7.0–8.0 and biological media (5% bovine serum albumin) at an ambient temperature and at 37°C. BG-AgNps showed effective antibacterial activity against Escherichia coli and Staphylococcus aureus. BG-AuNps and BG-AgNps demonstrated increased scavenging activity against 2,2-diphenyl-1-picrylhydrazyl free radicals. In addition, BG-AuNps and BG-AgNps were nontoxic to HaCaT and MCF-7 cells; the latter showed no cytotoxicity at concentrations lower than 10 µg/mL. At higher concentrations, BG-AgNps exhibited apparent apoptotic activity in MCF-7 breast cancer cell line through reactive oxygen species generation and nuclear fragmentation.

Keywords:

• gold nanoparticles
• silver nanoparticles
• monodispersity
• spectroscopy
• cytotoxicity
• antioxidant activity
• anticancer activity

Supplementary material

Figure S1 The content of ginsenosides in black ginseng.

Acknowledgments

This research was supported by the Korea Institute of Planning & Evaluation for Technology in Food, Agriculture, Forestry & Fisheries, Republic of Korea (KIPET NO: 316065031WT011[20161183]) and the Next-Generation BioGreen 21 Program (SSAC, grant#: PJ0120342016), Rural Development Administration, Republic of Korea.

Disclosure

The authors report no conflicts of interest in this work.