Comparative Study of Antimicrobial Activity of Silver, Gold, and Silver/Gold Bimetallic Nanoparticles Synthesized by Green Approach

Abstract

Nanotechnology is one of the most recent technologies. It is uncertain whether the production of small-size nanoparticles (NPs) can be achieved through a simple, straightforward, and medicinally active phytochemical route. The present study aimed to develop an easy and justifiable method for the synthesis of Ag, Au, and their Ag/Au bimetallic NPs (BNPs) by using Hippeastrum hybridum (HH) extract, and then to investigate the effects of Ag, Au, and their Ag/Au BNPs as antimicrobial and phytotoxic agents. Ag, Au, and their Ag/Au BNPs were characterized by UV-visible spectroscopy, FT-IR spectroscopy, XRD, EDX, and SEM analysis. XRD analysis conferring to the face of face-centered cubic crystal structure with an average size of 13.3, 10.72, and 8.34 nm of Ag, Au, and Ag/Au BNPs, respectively. SEM showed that Ag, Au, and Ag/Au BNPs had spherical morphologies, with calculated nano measurements of 40, 30, and 20 nm, respectively. The EDX analysis confirmed the composition of elemental Ag signal of the HH-AgNPs with 22.75%, Au signal of the HH-AuNPs with 48.08%, Ag signal with 12%, and Au signal with 38.26% of the Ag/Au BNPs. The Ag/Au BNPs showed an excellent antimicrobial efficacy against Gram-positive Staphylococcus aureus, Actinomycetes meriye, Bacillus cereus, Streptococcus pyogenes, Methicillin-resistant Staphylococcus aureus, Micrococcus luteus, Streptococcus pneumonia, and Gram-negative Klebsiella pneumonia, Escherichia coli, and Serratia marcescens bacterial strains, as well as against three fungal strains (Aspergillus niger, Aspergillus fumigatus, and Aspergillus flavus) compared to HH extract, HH-AgNPs, and HH-AuNPs. However, further investigations are recommended to be able to minimize potential risks of application.

Biogenic synthesis of gold nanoparticles using Heliotropium eichwaldi L and neuroprotective potential via anticholinesterase inhibition in rat brain

“…Small NPs possess the properties of agglomeration in bigger particles; due to this aggregate formation, the surface availability of NPs for organic molecules declines, whereas a space between NPs allows placement only for smaller molecules due to which the monomeric AChE can easily adsorb and interact with these agglomerated NPs. [34] According to [54][55][56] report, AuNPs have a binding affinity with the AChE enzyme that is based on their lipophilicity and hydrophobicity properties. According to the literature, no work has been done on AuNP synthesis from HE plant extract and their anti-AChE activity.…”

Synthesis, optimization, and characterization of silver/gold allied bimetallic from Hippeastrum hybridum (L.) and their ex vivo anti‐acetylcholinesterase activity in rat brain

“…Four different Bragg reflections, that is, 38.12°, 44.09°, 64.76°, and 77.44°, which corresponded to planes 1 1 1, 2 0 0, 2 2 0, and 3 1 1, respectively, were confirmed by JDX‐3532 (JEOL JAPAN) X‐ray diffractometer (Figure 3). These reflections confirmed the Ag and Au ions crystallite by comparing them with standard XRD analysis of Sher et al [ 2 ] The d (interplanar space) and a (Miller coefficients) were measured using formulas () and () and average size ( D ) was calculated by Debye‐Sherrer's calculation (iv). The average calculated size for the reported four peaks of BNPs was calculated to be 8.38 nm (0.00838 μm) (Table 2).…”

“…Similar results were also reported by previous works. [ 2,46 ] In the present research study, synthesis of BNPs under various dilutions of both Ag and Au salt and HH plant was achieved at 1 mM and 1 mL, respectively. Herbal plants are enriched with phytochemicals; however, these phytochemicals fluctuate from plant to plant dependent on the type, part, and nature of the selected plant, and also on the method of extraction of these phytochemicals.…”

“…The results are also supported by previous studies. [2,40] An ideal temperature of the reaction medium is also required for unique morphology NPs generation. [48] Therefore, in this study, NPs were synthesized different temperature ranges, that is, 20 C to 100 C. A sharp peak at 542 nm was reported at 40 C, whereas at all other temperatures, the peak becomes broader and absorbance also deviate from the ideal range.…”

“…Nowadays, metal NPs especially silver (Ag) and gold (Au) NPs are widely used in the fields of biomedical, antioxidant drug delivery, antimicrobial, antibiofilm, and anticancer. [1][2][3][4] According to the literature, AgNPs have been used for centuries as antibacterial agents. [5] AgNPs are also widely used in packaging, medical instrumental devices, food processing, biosensor, cosmetic products, and textiles.…”