Characterization and Biological Activity of Silver Nanoparticles Stabilized by Aqueous Extracts of Rubusspp. Leaves

Silver nanoparticles (AgNPs–E) biosynthesized at room and boiling T, stabilized by blackberry plant extracts (E) obtained by maceration at room T and reflux extraction at boiling T, are presented in this work. The obtained AgNPs–E were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), dynamic light scattering (DLS) and zeta-potential measurement. XRD analysis confirmed that the 2θ peak at 38.2°, corresponding to the (111) plane, was the most intense, with the average crystallite size in the range of 18.0 ± 3–21.1 ± 2 nm. SEM spectroscopy showed that spherical shapes of nanoparticles dominate in the reaction mixture. EDX spectroscopy showed the presence of elemental silver in the formed AgNPs–E, along with the presence of C and Mg, which probably originate from the biomolecules of the extracts. DLS provides the size distribution with the average particle size in the range of 50.93 ± 0.83–74.48 ± 1.84 nm, with negative zeta-potential ranged from –25.87 ± 1.63 to –0.3027 ± 0.36 mV indicating the AgNPs stability. The antimicrobial activity of AgNPs–E was tested by microdilution method confirming that both nanoparticles and extracts show the ability to inhibit all the bacteria and a fungus tested. The presented results suggest further investigations of synthesized AgNPs–E for application in topical cosmetic preparations.