Biological synthesis of gold nanoparticles is ecofriendly and effective for the development of environmentally sustainable nanoparticles compared with existing methods. Here, we developed a simple, fast, efficient, and... [ view full abstract ]
Biological synthesis of gold nanoparticles is ecofriendly and effective for the development of environmentally sustainable nanoparticles compared with existing methods. Here, we developed a simple, fast, efficient, and ecofriendly approach to the synthesis of gold nanoparticles by means of a Gardenia jasminoides extract. These G. jasminoides extract-capped gold nanoparticles (GJ-GNPs) were characterized by UV-Vis, high resolution transmission electron microscopy (HR-TEM), X-ray diffraction (XRD), and Furrier transform infrared spectroscopy (FT-IR). The synthesized GJ-GNPs turned red and showed maximal absorbance at 540 nm. Thus, GJ-GNPs were synthesized successfully, and GJ-GNPs were found to have roughly spherical and hexagonal shapes, and monodispersed, with the diameter of particles 20 nm. The synthesized GJ-GNPs were confirmed to be crystalline in nature.
Prematurely senescent cells are known to have characteristics of replicative senescence, such as a loss of the proliferative potential, enlarged and flattened cell shape, irreversible cell cycle arrest, and increased senescence-associated β-galactosidase (SA-β-gal) activity. We hypothesized that GJ-GNPs would protect ARPE19 cells from hydrogen peroxide-induced premature senescence. We tested the effects of hydrogen peroxide (at various concentrations) on ARPE19 cell senescence and showed that low concentrations of hydrogen peroxide induced positive staining of SA-β-gal and arrested cell cycle progression. Thus, hydrogen peroxide treatment induced premature senescence in ARPE19 cells, as indicated by the changed cellular morphology. Treatment with GJ-GNPs restored the hydrogen peroxide-induced morphological changes. SA-β-gal activity was elevated in hydrogen peroxide-treated cells, however, this effect was attenuated by GJ-GNP treatment. Moreover, compared with the normal control, hydrogen peroxide treatment significantly increased lysosome content of the cells and production of reactive oxygen species (ROS). GJ-GNPs effectively attenuated the increase in lysosome content and ROS production in these senescent cells. According to cell cycle analysis, G2/M arrest was promoted by hydrogen peroxide treatment in ARPE19 cells, however, this change was reversed by GJ-GNPs. Western blot analysis showed that treatment with GJ-GNPs increased the expression of p53, p21, SIRT3, HO-1, and NQO1 in senescent cells. Our findings should advance the understanding of premature senescence and may lead to therapeutic use of GJ-GNPs in retina-related regenerative medicine.
