Antibacterial Activity of Mono and Bimetallic Au:Ag Colloidal Nanoparticles Prepared by Pulse Laser ablation PLA

Abstract

Au, Ag mono and Bimetallic Au:Ag colloidal nanoparticles were synthesized in two steps using pulsed laser ablation in liquid technique (pure Au, Ag metal plates of immersed in deionized water). The pulse laser (Q-switched,  Nd: YAG)1064 nm with energy 700 mJ, frequency 5 Hz and 200 laser pulses at room temperature have been used. Absorbance (SPR band), size, surface morphology and structure of the synthesized Nps have been studied and investigated by UV-Vis spectrophotometer, transmission electron microscopy, and x-ray diffraction. The absorbance spectrum of Au, Ag and Au:Ag nanoparticles shows sharp and single peaks around 513 nm, 398 nm and 523 nm respectively. This gives indicate that the production of pure and spherical Au and Ag NPs with average size in the range 16 - 100 nm. The particles size measurements were confirmed by TEM. The Au:Ag nanoalloy appears to be nearly spherical with an average size ranging from 29 to 72 nm and the SPR band at (450 nm ). The XRD result showed very low crystallinity structure. The antibacterial activity of Au, Ag and bimetallic Au:Ag NPs were evaluated for NPs  obtained by PLAL using applied pulses (100,150,200) in DI water, on the Gram-positive isolate (Staphylococcus aureus) and Gram-negative isolate (Escherichia coli). The results and images of inhibition zones diameter showed that the NPs have synergistic effects on the studied bacteria up to 15 mm and 4 mm at the highest and lowest values and it increase with the increase of laser pulses number.