Green Synthesis and Antimicrobial Potential of Silver/Gold Nanoparticles Functionalized with Debregeasia salicifolia D. Don

Biosynthesis of Bimetallic Cu-Ag Nanocomposites and Evaluation of their Electrocatalytic, Antibacterial and Anti-Cancerous Activity

Bimetallic nanocomposites have evolved into a significant smart material in the recent past. Owing to the growing interest, we herein report the biosynthesis of bimetallic silver doped copper (Cu-Ag) nanocomposites using green methods by utilizing aqueous extract of Carica papaya leaves. The optical property and the surface morphology of the nanoparticles were determined by using various analytical techniques like Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Analysis (EDAX) and Transmission Electron Microscopy (TEM). The redox behaviour of the bimetallic nanocomposites was studied using Cyclic Voltammetry (CV) with platinum electrode in 0.1M KCl solution at different scan rates and concentrations. The FTIR revealed the presence of active components of the leaf extract which played the roles of surfactants, stabilizing, capping, and reducing agents. Similarly, SEM with EDAX exhibited the presence of spherically agglomerated Cu-Ag nanocomposites and TEM images revealed a particle size of 20 nm. The gradual increase in peak current was observed in CV with increase in the scan rates and concentrations apparently. The bimetallic nanocomposites showed potential anti-bacterial, anti-cancerous activity and the reports are provided in detail.

Synthesis, Characterization and Bioactivity Profiling of Gold Nanoparticles of Trachyspermum ammi Crude Extract

Trachyspermum ammi seeds were selected for photochemical study. The crude T. ammi methanol and aqueous extracts showed the presence of alkaloids, saponins, steroids, terpenoids, coumarins, betacyanins, flavonoids and soluble starch. The synthesis of gold nanoparticles (AuNPs) using T. ammi extract was characterized using UV-visible, and FT-IR spectroscopy. The appearance of sharp peak at 520 nm in the UV visible spectra, and the appearance of broad band nanoparticles spectra at 563.21 cm-1, 516.92 cm-1 and 462.92 cm-1 as well as the disappearance of the carboxyl OH bond and carbon-carbon triple bond supported the formation of AuNPs. The crude T. ammi methanol and AuNPs were investigated for antioxidant potential using DPPH· free radical assay, which shows that crude extract has significant antioxidant effect. The synthesized AuNPs was also evaluated for antibacterial activities against staphylococcus aureus, Klebsiella pneumonia and Bacillus subtilis. The crude extract showed activity against Bacillus subtilis, while AuNPs showed activity against staphylococcus aureus. The in vivo sedative effect and analgesic effect were enhanced in AuNPs treated animals in 5 times less dose (i.e., 5, and 10 mg/kg) than that of crude extract. It was concluded that T. ammi extract include capping and reducing agents, which make it capable to be developed as stable AuNPs. The biological action of AuNPs is either enhanced (sedative and analgesic) or changed (antibacterial activity), when compared with that of plant extract.