Gold nanoparticles using red seaweed Gracilaria verrucosa: Green synthesis, characterization and biocompatibility studies

In the present study, multifaceted gold nanoparticles (AuNPs) were obtained by using Gracilaria verrucosa via facile green one-pot synthesis and characterized by means of high throughput techniques. Further, the obtained multifaceted AuNPs were tested for biocompatibility against normal human embryonic kidney (HEK-293) cell lines. The results from the study revealed the occurrence of both isotropic and anisotropic nanoparticles as evidenced by UV-vis spectroscopy (520 nm), Transmission Electron Microscopy (isotropic and anisotropic AuNPs of size between 20-80 nm), X-ray diffraction analysis (crystalline gold metal), particle size distribution (73.12 nm) and zeta potential analysis (-21.3 mV). Moreover, Fourier Transform - Infrared spectroscopy (FT-IR) disclosed the presence of proteins, phenolic and aromatic compounds that acted as capping/stabilizing agents during the formation of AuNPs. Further, the AuNPs synthesized using G. verrucosa showed no cytotoxic effect against HEK-293 cells as verified by MTT and trypan blue exclusion assays. In the end, AuNPs displayed effective cellular uptake within HEK-293 cells as substantiated by the fluorescence microscopic studies. To the best our knowledge, this is the first report on the synthesis of AuNPs using the marine red seaweed G. verrucosa and evaluation of their biocompatibility using human embryonic kidney (HEK-293) cells.