No abstract

A facile and green route for the synthesis of palladium nanoparticles from palladium chloride was developed using non-toxic, renewable plant polymer, gum ghatti (Anogeissus latifolia), as both the reducing and stabilizing agent. The generated nanoparticles were characterized with UV-visible spectroscopy (UV-vis), dynamic light scattering (DLS), transmission electron microscopy (TEM), and X-ray diffraction (XRD) techniques. The formation of palladium nanoparticles was confirmed from the appearance of intense brown colour and broad continuous absorption spectra in the UV-visible region. The produced nanoparticles were found to be spherical in shape, polydisperse and the average particle size was 4.8 ± 1.6 nm. The face centred cubic crystal structure of the fabricated nanoparticles is confirmed from the selected-area electron diffraction and XRD patterns. Compared to earlier reports, the nanoparticles showed superior antioxidant at a much lower nanoparticle dose. Also, the homogenous catalytic activity of palladium nanoparticles was studied by probing the reduction of dyes such as coomassie brilliant blue G-250, methylene blue, methyl orange, and a nitro compound, 4-nitrophenol with sodium borohydride. The nanoparticles exhibited excellent catalytic activity in dye degradation and the results of this study demonstrate the possible application of biogenic palladium nanoparticles as nanocatalyst in environmental remediation. ª 2015 The Authors. Production and hosting by Elsevier B.V. on behalf of King Saud University. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

The nanoparticles used in this study were prepared from AgNO3 using NaBH4 in the presence of capping agents such as citrate, sodium dodecyl sulfate, and polyvinylpyrrolidone. The formed nanoparticles were characterized with UV-Vis, TEM, and XRD. The generation of silver nanoparticles was confirmed from the appearance of yellow colour and an absorption maximum between 399 and 404 nm. The produced nanoparticles were found to be spherical in shape and polydisperse. For citrate, SDS, and PVP capped nanoparticles, the average particle sizes were 38.3 ± 13.5, 19.3 ± 6.0, and 16.0 ± 4.8 nm, respectively. The crystallinity of the nanoparticles in FCC structure is confirmed from the SAED and XRD patterns. Also, the combined antibacterial activity of these differently capped nanoparticles with selected antibiotics (streptomycin, ampicillin, and tetracycline) was evaluated on model Gram-negative and Gram-positive bacteria, employing disc diffusion assay. The activity of the tested antibiotics was enhanced in combination with all the stabilized nanoparticles, against both the Gram classes of bacteria. The combined effects of silver nanoparticles and antibiotics were more prominent with PVP capped nanoparticles as compared to citrate and SDS capped ones. The results of this study demonstrate potential therapeutic applications of silver nanoparticles in combination with antibiotics.