Catalytic and antibacterial properties of gold nanoparticles synthesized by a green approach for bioremediation applications

Abstract

In this work, we are proposing the green synthesis of gold nanoparticles (AuNPs) using aqueous extracts of A. triphylla and evaluating their antibacterial and catalytic properties. Characterization was performed by UV-Vis and FT-IR spectroscopies, X-ray diffraction, and transmission electron microscopy (TEM). Antibacterial activity of AuNPs was analyzed using E. coli and S. Aureus and catalytic activity was determined by the degradation of methylene blue and congo red. UV-Vis analysis showed an increase in AuNPs concentration by increasing the extract concentration, volume extract, and precursor salt concentration. The crystalline nature of AuNPs was corroborated by X-ray diffraction. TEM analysis showed nanoparticles with spherical morphology (mostly) and size between 40 and 60 nm. These results are novel because they showed a homogeneous morphology and a narrow size distribution which is difficult to obtain in green synthesis processes. Results of antibacterial activity showed inhibition zones of 11.3 mm and 10.6 mm for S. Aureus and E. coli, respectively, indicating the bactericidal capacity of the nanoparticles. The degradation periods for methylene blue and congo red were 5 and 11 min, respectively, which are very short compared with previous reports. These results are of great significance for catalytic applications. Therefore, A. triphylla extracts made possible AuNPs synthesis and the nanoparticles obtained can be used as catalytic and antibacterial materials for water remediation.

Phytofabrication of gold and bimetallic gold-silver nanoparticles using water extract of wheatgrass (Triticum aestivum), their characterization and comparative assessment of antibacterial potential

“…After that, the extract was first filtered through Whatman filter paper (1) and followed by centrifugation for 7-8 minutes at 8000 rpm to remove any remaining plant-debris or impurities. This extract was used for the fabrication of both AuNPs and BMNPs (5,18).…”

“…Synthesis of AuNPs and BMNPs (Ag -Au NPs) were confirmed by scanning the absorption maxima of both AuNPs and BMNPs using UV -visible spectrophotometer (Thermo Fisher Scientific, India) in the wavelength range of 300-700 nm. The FTIR analysis was determined with FTIR spectrometer (Perkin Elmer) at a resolution of 4 cm − 1 in the wavelength range of 4000-250 cm -1 (5,8,18). The obtained FTIR spectra were plotted as absorbance (%) versus wavenumber (cm -1 ).…”

“…Nobel metals like, gold nanoparticles (also known as colloidal gold) attract the attention of researchers due to their inherent superior physico-chemical characteristics like high surface area, chemically inertness (resistance to oxidation), higher stability in comparison to other metallic nanoparticles (NPs), enhanced biocompatibility and non-cytotoxicity to human cells and tissues. These aforementioned properties resulted in their tremendous applications in the field of medicine and other related fields such as magnetic, optical, electronic, catalytic (3,4), bio-imaging, nano-biosensing, probes and markers, targeted drug delivery (5), photohyperthermia, water remediation, genetic engineering, diagnosis and therapeutics (6,7).…”

Multifunctional Activities of Gold Nanoparticles Biosynthesized Using Bacteria Isolated from Mining Areas

“…First, high AuNPs concentration was required to achieve satisfactory efficiency; for example, 60-2000 mg/L biogenic AuNPs was required to degrade dye [20,25,35]. Second, only treatment with dilute dye concentration did not fulfil the actual requirements of dye treatment; for example, treatment with 5-22.4 mg/L MB was insufficient [20,25,36]. Finally, only in the presence of NaBH 4 , strong photocatalytic activity was achieved for efficient degradation of dyes [24].…”

Au–ZnO Conjugated Black Phosphorus as a Near-Infrared Light-Triggering and Recurrence-Suppressing Nanoantibiotic Platform against Staphylococcus aureus

“…ZO exhibits not only excellent antibacterial properties, but a remarkable ability to inhibit the recurrence of drug resistance by bacteria, as shown in our previous study [ 23 ]. Furthermore, although Au NPs represent the major catalytic and antibacterial components [ 10 , 24 ], they must be pre-treated with ligands to increase their stability, which often affect the intrinsic physicochemical characteristic and subsequent activity of these materials. Therefore, it would be beneficial to develop Au NPs without compromising their essential properties or employing any surfactants.…”