Arabic Gum as Bio-Synthesizer for Ag-Au Bimetallic Nanocomposite Using Seed-Mediated Growth Technique and Its Biological Efficacy

Bio-synthesis of nanostructures is an ever green approach; therefore, the current work attempts to use Arabic gum as bio-synthesizer for manufacturing Ag-Au bimetallic nanocomposite, using seed-mediated growth technique. The relevance of the as-used natural gums for manufacturing of Ag-Au nanocomposite in quite simple, energy saving and cost effective methodology, has been successfully approved. Arabic gum acted concurrently as a reducer for metal ions to nano-sized structures and crystal growth modifier of the so-generated nanocomposite. Monitoring of interchanging in size distribution of the as-produced bimetallic nanocomposite by the effect of the gum concentration, concentration of nanometals precursors, their addition sequencing in reaction liquor, and reaction temperature, was illustrated and well characterized. UV-Visible spectra showed that the characteristic surface plasmon resonance peak for Ag-Au bimetallic nanocomposite was observed at 480-495 nm and XRD patterns confirmed the preparation of bimetallic nanostructures. According to zetasizer analyses and TEM micrographs, small sized (3.1 nm) Ag-Au bimetallic nanocomposite with narrow size distribution (1-7 nm) were obtained. The all prepared bimetallic nanocomposite showed good stability with polydispersity index ranged in 0.203-0.530. The mechanism of nanostructures' generation was suggested and approved using FT-IR, 1HNMR and 13CNMR spectra. The prepared Ag-Au bimetallic nanocomposites showed excellent antibacterial activity against both of gram + ve and gram - ve strains.