PEGylated silver nanoparticles from Sesbania aegyptiaca exhibit immunomodulatory and anti-cancer activity

In the present study, silver nanoparticles were synthesized by Sesbania aegyptiaca leaf extract and it was coated with Polyethyleneglycol (PEG), to improve its stability. Physical properties of both Ag and PEG-Ag nanoparticles were characterized byUV-Vis spectrophotometer, XRD, FT-IR, EDX, and SEM. The physical characterization confirms that the Ag and PEG-Ag nanoparticles were in round shape and the size ranges between 16-23 and 25-28 nm, respectively. Further, immunomodulatory and anti-cancer effect of PEG-Ag NPs were studied in vitro with macrophage (RAW264.7) and HeLa cells, respectively. The toxic effect of PEG-Ag NPs against macrophage and HeLa cells were studied by MTTassay; results revealed that at the concentration of 1.5 mu gml(-1) the growth of HeLa cells was inhibited to 50%; however, no toxic effect was observed against macrophages at this concentration until 72 h. PEG-Ag NPs promote the growth of macrophages at 1 mu gml(-1); also, unveil toxicity beyond 1.5 mu gml(-1). Stimulatory effect of PEG-Ag NPs was studied with cell sprouting and NBTassays. Subsequently, the influence of PEG-Ag NPs on innate immune system was studied in vivo with mice model system; the finding from in vitro and in vivo experiments revealed that the PEG-Ag NPs have significant role on stimulating immune cells and controlling cancer progression.