Rapid efficient synthesis and characterization of silver, gold, and bimetallic nanoparticles from the medicinal plant Plumbago zeylanica and their application in biofilm control

Abstract

BackgroundNanoparticles (NPs) have gained significance in medical fields due to their high surface-area-to-volume ratio. In this study, we synthesized NPs from a medicinally important plant – Plumbago zeylanica.Materials and methodsAqueous root extract of P. zeylanica (PZRE) was analyzed for the presence of flavonoids, sugars, and organic acids using high-performance thin-layer chromatography (HPTLC), gas chromatography-time of flight-mass spectrometry (GC-TOF-MS), and biochemical methods. The silver NPs (AgNPs), gold NPs (AuNPs), and bimetallic NPs (AgAuNPs) were synthesized from root extract and characterized using ultraviolet-visible spectra, X-ray diffraction (XRD), energy-dispersive spectrometry (EDS), transmission electron microscopy (TEM), and dynamic light scattering (DLS). The effects of these NPs on Acinetobacter baumannii, Staphylococcus aureus, and Escherichia coli biofilms were studied using quantitative biofilm inhibition and disruption assays, as well as using fluorescence, scanning electron microscopy, and atomic force microscopy.ResultsPZRE showed the presence of phenolics, such as plumbagin, and flavonoids, in addition to citric acid, sucrose, glucose, fructose, and starch, using HPTLC, GC-TOF-MS, and quantitative analysis. Bioreduction of silver nitrate (AgNO3) and chloroauric acid (HAuCl4) were confirmed at absorbances of 440 nm (AgNPs), 570 nm (AuNPs), and 540 nm (AgAuNPs), respectively. The maximum rate of synthesis at 50°C was achieved with 5 mM AgNO3 within 4.5 hours for AgNPs; and with 0.7 mM HAuCl4 within 5 hours for AuNPs. The synthesis of AgAuNPs, which completed within 90 minutes with 0.7 mM AgNO3 and HAuCl4, was found to be the fastest. Fourier-transform infrared spectroscopy confirmed bioreduction, while EDS and XRD patterns confirmed purity and the crystalline nature of the NPs, respectively. TEM micrographs and DLS showed about 60 nm monodispersed Ag nanospheres, 20–30 nm Au nanospheres adhering to form Au nanotriangles, and about 90 nm hexagonal blunt-ended AgAuNPs. These NPs also showed antimicrobial and antibiofilm activity against E. coli, A. baumannii, S. aureus, and a mixed culture of A. baumannii and S. aureus. AgNPs inhibited biofilm in the range of 96%–99% and AgAuNPs from 93% to 98% in single-culture biofilms. AuNPs also showed biofilm inhibition, with the highest of 98% in S. aureus. AgNPs also showed good biofilm disruption, with the highest of 88% in A. baumannii.ConclusionThis is the first report on rapid and efficient synthesis of AgNPs, AuNPs and AgAuNPs from P. zeylanica and their effect on quantitative inhibition and disruption of bacterial biofilms.

Platanus orientalis Leaf Mediated Rapid Synthesis of Catalytic Gold and Silver Nanoparticles

“…The bioreduced nanoparticles exhibited anisotropic morphology with exotic shapes like nanotriangles, spheres and blunt ended hexagons. Similar anisotropy was reported during synthesis using Dioscorea bulbifera and Plumbago zeylanica [10,11,19]. P. orientalis was found to possess various phytochemicals like phenolic, citric acid, ascorbic acid and reducing sugars which might help in reduction while starch may play a key role in stabilization.…”

“…Biochemical assays were used to evaluate total phenolic content, starch, reducing sugar, ascorbic acid and citric acid in POLE according to our earlier report [10]. Further, GCMS fingerprinting was employed to estimate the predominant phytochemicals in POLE [10,[16][17][18][19].…”

“…Hereby, herbal extracts rich in diverse groups of phytochemicals is preferred for simultaneous synthesis and capping of metal nanoparticles [8,9]. Medicinal plants like Dioscorea bulbifera, Dioscorea opposiifolia, Barleria prionitis, Gloriosa superba, Gnidia glauca, Plumbago zeylanica, have exhibited their nanobiotechnological potential towards synthesis of gold, silver, copper, platinum and palladium nanoparticles with biological activities [10][11][12][13][14][15][16][17][18][19]. Earlier reports showed that the phytogenic nanoparticles were more biocompatible and bioactive as compared to the chemically synthesized nanoparticles [13,19].…”

Lactococcus lactis as a safe and inexpensive source of bioactive silver composites

“…However, most of them demand hazardous chemicals, toxic byproducts, and high energy consumption (Cherusova and Epple 2013 ). Recently, biological methods of silver nanoparticles synthesis using green algae, bacteria, fungi, and plant extracts are gaining impetus due to their low costs and simplicity (Singh et al 2013 ; Salunke et al 2014 ). The properties of synthesized nanoparticles depend on used bacterial strain, type of medium, pH, and temperature.…”

Biogenic Synthesis of Novel Functionalized Selenium Nanoparticles by Lactobacillus casei ATCC 393 and Its Protective Effects on Intestinal Barrier Dysfunction Caused by Enterotoxigenic Escherichia coli K88

“…are usually used for the chemical synthesis of SeNPs, which are involved in lines of catalytic reduction ( Hong Lin et al, 2004 ; Zhang et al, 2010 ; Dwivedi et al, 2011 ). Previous researches indicate that certain bacteria ( Cui et al, 2016 ), fungi ( Vetchinkina et al, 2013 ), and plants ( Salunke et al, 2014 ) can mediate the biological synthesis of SeNPs. However, in the process of preparation of SeNPs, unsafe factors brought by physical and chemical methods limit the development and wide application of SeNPs in food, biomedicine, and feed additives ( Iranifam et al, 2013 ).…”