Bio-Synthesis and Characterization of Silver Nanoparticle and Silver-Bentonite Nanocomposite Using Hagenia abyssinica Leaf Aqueous Extract and Assessment of its Anti-Bacterial Activity.

Abstract

In this study, rapid, simple approach was applied for synthesis of environmental friendly nano-material. Silver Nanoparticles (AgNPs) and Silver Nanoparticle Bentonite (Bent) Nanocomposite (Ag-Bent NCs) were prepared using H. abyssinica leaf extract as reducing and capping agent for antibacterial application. Various advanced techniques like: X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy Ultraviolet-visible (UV-Vis) spectrophotometer and Atomic absorption spectroscopy (AAS) were used to characterize bentonite, AgNPs and Ag-Bent NCs for the phase analysis, crystallites size, functional group and compositional analysis respectively. UV-Visible spectrophotometer revealed the absorbance peak in range of 410-423nm for AgNPs and 368nm of AgNPs and 488nm of Bentonite in Ag-Bent NCs. XRD analysis result indicated that the synthesized AgNPs and Ag-Bent NCs found to possess a FCC structure. The average crystallite size of the Ag NPs estimated from XRD diffraction pattern using Debye Scherrer’s formula was found to be 21.76nm for the 1:4 ratio of AgNO3 to leaf extract in volume that capped nanomaterial and has a smaller particle size than the others. XRD results for Ag-Bent show that Ag NPs and bentonite are well combined in synthesizing Ag-Bent NCs. The FTIR analysis shows the presence of hydroxyl, carbonyl, alkyl, amide, alcohol and nitro functional group in NPs and NCs. And also shows the weak interaction between silver nanoparticles with the surface of Bentonite due to the presence of van der Waals interactions. AgNP demonstrated high-antibacterial activity against Staphylococcus aureus (Gram positive) as evaluated by means of inhibition zone of 15nm and Ag-Bent is good for both gram positive and negative bacteria but best for gram negative (Escherichia coli) bacteria with inhibition zone of 20nm, compared to ciprofloxacin which was used as a positive control in Agar disk diffusion method.