Biosynthesis of silver nanoparticles using Azadirachta indica leaves: characterisation and impact on Staphylococcus aureus growth and glutathione‐S‐transferase activity

Abstract

Silver nanoparticles (AgNPs) are toxic to various microbes, but the mechanism of action is not fully understood. The present report explores Azadirachta indica leaf extract as a reducing agent for the rapid biosynthesis of AgNPs. The effects of AgNPs on the growth, glutathione-S-transferase (GST) activity, and total protein concentration in Staphylococcus aureus were investigated, as was its antibacterial activity against seven other bacterial strains. Nanoparticle synthesis was confirmed by the UV-Vis spectrum and colour change of the solution. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), dynamic light scattering (DLS), zeta potential analysis, and infrared spectroscopy were used to characterise the synthesised nanoparticles. The UV-Visible spectrograph showed an absorbance peak at 420 nm. DLS analysis showed an average AgNP size of 159 nm and a Polydispersity Index of 0.373. SEM analysis showed spherical particle shapes, while TEM established an average AgNP size of 7.5 nm. The element analysis profile showed small peaks for calcium, potassium, zinc, chlorine, with the presence of oxygen and silver. AgNPs markedly affected the growth curves and GST activity in treated bacteria, and produced moderate antibacterial activity. Thus AgNPs synthesised from A. indica leaves can interrupt the growth curve and total protein concentration in bacterial cells.

Non-enzymatic glucose detection with screen-printed chemiresistive sensor using green synthesised silver nanoparticle and multi-walled carbon nanotubes-zinc oxide nanofibers

“…Here in our proposed work, we have taken the concentration of leaf extract as 3 ml since it effectively worked as an antimicrobial assay at this particular concentration [38]. The obtained results are well match with earlier reported literature [44][45][46][47][48][49][50][51][52][53][54][55][56][57][58][59].…”

Phytosynthesis of Silver Nanoparticles Using Perilla frutescens Leaf Extract: Characterization and Evaluation of Antibacterial, Antioxidant, and Anticancer Activities

“…44 The polydispersity index (PI) and zeta potential values were recorded using dynamic light scattering (DLS; Brookhaven Instruments). 45 Antibacterial Activity of PF@AgNPs For this study, we selected both gram-negative (E. coli) and gram-positive (B. subtilis and S. aureus) pathogens. Bacterial cultures were activated 24 h prior to the assay.…”

Biogenic Silver Nanoparticles from Two Varieties of Agaricus bisporus and Their Antibacterial Activity

“…The main problem faced by chemical methods is the use of harmful solvents and reducing agents with costly metal salts [ 19 ]. To overcome these challenges, researchers get encouraged by the biological approach to fabricating nanoparticles by using extracts from organisms such as plants [ 20 ], bacteria [ 21 ], fungi [ 22 ], and algae [ 23 ] for reducing metal salts to metal nanoparticles. The stability of these nanoparticles is enhanced by capping with biomolecules present in the organism [ 24 ].…”

“…Many studies have reported biological approaches to nanoparticle production from edible mushrooms [ 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 ]. Edible mushrooms are rich in protein and are enriched with essential amino acids.…”