Green synthesis, characterization and biomedical potential of Ag@Au core–shell noble metal nanoparticles

In the current times, nanotechnology has emerged as a field that promises scientific advancement with the manipulation, improvement, and application of near-atomic scale materials.Bimetallic nanoparticles (NPs) have been explored for their wide range of applications owing to their multi-functionalilty. The present study included the synthesis of bimetallic silver@gold (Ag@Au) NPs from aqueous chloroauric acid (HAuCl 4 ) and silver nitrate (AgNO 3 ) making use of ‘green chemistry’ with the extract of Acacia nilotica husk as a reducing and capping agent. The formed bimetallic NPs were characterized by various spectrometry and electron microscopy techniques and devices, including ultraviolet–visible spectroscopy (UV/VIS), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDS) attached to scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), and the particle size distribution was analyzed by dynamic light scattering (DLS) technique. FTIR results identified the functional groups that are involved in and interact with biomolecules and nanoparticles surfaces through extensive screening on synthesized colloidal bimetallic NPs. The synthesized core – shell had mean size and monodispersity index (PDI) values of 0.223 and 61 nm, respectively. TEM micrographs clearly indicated that the Au NPs were coating and surrounding the Ag NPs and their size, distribution and shapes were homogeneous and uniform. Anticancer activity of the synthesized Ag@Au NPs was explored using MTT assay; the recorded cell viability was 500 μg/ml and the cytotoxicity (IC50) was 74.6 ± 7.43 µg/ml for HeLa cell line. This anticancer activity of the Ag@Au NPs opens the window wide for their use in cancer therapy and other biomedical applications.