Quercetin- and caffeic acid-functionalized chitosan-capped colloidal silver nanoparticles: one-pot synthesis, characterization, and anticancer and antibacterial activities.

The presented study comprises the one-pot synthesis and the characterization of quercetin- and caffeic acid-functionalized chitosan-capped colloidal silver nanoparticles (Ch/Q- and Ch/CA-Ag NPs), and their antibacterial and anticancer activities. The formation of Ch/Q- and Ch/CA-Ag NPs has been confirmed by ultraviolet-visible (UV-vis) spectroscopy, Fourier-transform infrared (FTIR) spectroscopy, and transmission electron microscopy (TEM). The characteristic surface plasmon resonance (SPR) absorption band has been found at 417 and 424 nm for Ch/Q- and Ch/CA-Ag NPs, respectively. The formation of a chitosan shell comprising quercetin and caffeic acid, which surround the colloidal core Ag NPs, was confirmed by UV-vis, and FTIR analyses, and monitored by TEM microscopy. The size of nanoparticles has been determined as 11.2 and 10.3 nm for Ch/Q- and Ch/CA-Ag, respectively. The anticancer activity of Ch/Q- and Ch/CA-Ag NPs has been evaluated against U-118 MG (human glioblastoma) and ARPE-19 (human retinal pigment epithelium) cells. Both NPs showed anticancer activity, but Ch/Q-Ag NPs seemed to be more effective on cancer cell lines (U-118 MG) in comparison to healthy ones (ARPE-19). Furthermore, the antibacterial activity of Ch/Q- and Ch/CA-Ag NPs against Gram-negative ( P. aeruginosa and E. coli ) and Gram-positive ( S. aureus and S. epidermidis ) bacteria was determined, and dose-dependent antibacterial effects were found.