Sneha KrishnamurthyCourtney, Samantha J.2019-06-202019-06-202019-05http://hdl.handle.net/20.500.11868/759Gold nanoparticles are found in consumer products that affect the skin such as cosmetics and anti-aging creams. This study explored the concentration dependent cytotoxic effects of both biogenic AuNPs and chemically synthesized citrate-capped AuNPs on human dermal fibroblast (HDF) cells. First, biogenic gold nanoparticles (AuNPs) were synthesized with 0.5 mM HAuCl4•3H2O using Camellia sinensis (black tea) as a reducing agent. Then, the crystallinity, size, and charge of the nanoparticles in suspension were analyzed by high-resolution transmission electron microscopy (HR-TEM), dynamic light scattering, and zeta potential analysis. Next, we analyzed the effects of AuNP concentration and exposure time on HDF cells. Immunofluorescence microscopy was performed using phalloidin and 4, 6 Diamidine-2-phenylindole dihydrochloride (DAPI) to analyze their effects on the actin filaments and nuclei of HDF cells. We assessed cell proliferation and viability using MTT assay, LDH assay, and flow cytometry. These results showed that the cytotoxic effects were similar for biological and chemical AuNPs, and at 72 hours of exposure, both AuNPs caused an increase in cell growth. Overall, there is no significant difference in the toxicity of biological and chemical AuNPs. In the future, we will analyze HDF cell gene expression after AuNP exposure with real-time PCR. Created as an independent study under the direction of Prof. Sneha Krishnamurthy.en-USGold nanoparticlesBiogenic AuNPsChemically synthesized citrate-capped AuNPsHuman dermal fibroblast cellsHDFCamellia sinensisCosmeticsAnti-aging creamsResearch Subject Categories::NATURAL SCIENCESPresentation