A facile synthesis of silver nanoparticle with SERS and antimicrobial activity using Bacillus subtilis exopolysaccharides

In this study, we report a facile synthesis of silver nanoparticle having SERS and antimicrobial activity using bacterial exopolysaccharide (EPS). Bacillus subtilis (MTCC 2422) was grown in nutrient broth and the extracellular EPS secreted by the organism was extracted and purified. The purified EPS was used for the synthesis of silver nanoparticles. The kinetics of silver nanoparticle synthesis was deduced by varying the exposure time and the concentration of EPS. The rate constant (k) for the synthesis of silver nanoparticle was calculated from the slope of ln(A^∞ ? A^t) versus time plot. The k value was found to be 3.49 × 10^?3, 5.81 × 10^?3 and 5.03 × 10^?3 per min for particle synthesis using 2, 5 and 10 mg/mL EPS, respectively. The nanoparticles synthesised had an average particle size of 5.18 ± 1.49 nm, 1.96 ± 0.77 nm and 2.08 ± 0.88 nm for 2, 5 and 10 mg/mL EPS, respectively. The synthesised particles were characterised using UV-Vis absorbance spectroscopy, high-resolution transmission electron microscopy (HRTEM) attached to EDS (energy dispersive spectroscopy), Fourier transform infrared spectroscopy (FTIR), surface enhanced Raman spectroscopy (SERS) and zeta potential analyser. To our knowledge, this is the first study to report SERS activity of microbial Bacillus subtilis EPS-based synthesis of silver nanoparticle. HRTEM images showed silver nanoparticle entrapped in polysaccharide nanocages. Silver nanoparticle showed higher adherence towards the bacterial surface, with good bactericidal activity against Pseudomonas aeroginosa and Staphylococcus aureus.     

Synthesis of silica/Au core-shell nanostructures by galvanic replacement of silica/Ag in aqueous and alkaline medium

We present here a facile one-step method for the synthesis of silica/Au core-shell nanostructures by exploiting the potential difference of AuCl₄^? and Ag in aqueous as well as alkaline media. Initially, silica/Ag core-shell nanostructures were synthesised by coating Ag nanoparticles on silica core (size ～150 nm) in a two-step process (seeding and growth) and were characterised for their morphological, structural and optical behaviours. A complete coverage of silica core with Ag nanoparticles was seen from scanning electron microscope and transmission electron microscope images. The presence of resonance peaks in the optical spectrum manifests the nature of the shell (thin shell ～413 and 650 nm, thick shell ～434 nm). Galvanic replacement of silica/Ag core-shell nanostructures in chloroauric acid solution (HAuCl₄) was studied in both the aqueous and alkaline medium, where an aqueous environment results into fast and effective replacement as compared to an alkaline medium, which has been confirmed from optical absorption studies. The optical studies showed that in an alkaline environment, on galvanic replacement of Ag with Au, the individual absorption peak of Ag (～414 nm) and Au (～520 nm) disappeared, whereas new absorption wavelengths in higher region (600–800 nm) of electromagnetic spectrum were observed. A detailed mechanism is proposed for the same to explain this behaviour. A range of novel new plasmonic core-shell nanomaterials can be synthesised as an intermediate of this facile one-step reaction.     

Ipomea carnea-based silver nanoparticle synthesis for antibacterial activity against selected human pathogens

The biosynthesis of silver nanoparticles (AgNps) has a wide range of applications, and here we develop a rapid synthesis using the leaf extract of Ipomea carnea. We demonstrated that 100?mL of a 1?mM silver nitrate solution was reduced to AgNps by 500?µL of I. carnea extract in 5?min and that one or more of the chemical constituents present in the extract acted as the reducing agent. Surface plasmon resonance peaks were observed from 410 to 440?nm for AgNps synthesised using the plant extract, and the peaks showed a characteristic blue shift with variation of pH from 2 to 8. Particle size analysis revealed the size of the AgNps to be from 30 to 130?nm, which was also confirmed by dynamic light scattering, atomic force microscopy and transmission electron microscopy. Additionally, the antibacterial effects of the AgNps were evaluated against selected human pathogens such as Staphylococcus aureus, Bacillus cereus, Bacillus subtilis, Klebsiella pneumoniae, Aeromonas hydrophila, Salmonella typhi, Proteus vulgaris and Pseudomonas aeruginosa. Finally, the AgNps were impregnated with a cellulose acetate membrane to form an antimycobacterial membrane. Antimycobacterial activity against a non-pathogenic Mycobacterium smegmatis showed that the AgNp-embedded membrane system has a zone of inhibition of 14?mm.     

Picosecond nonlinear optical studies of gold nanoparticles synthesised using coriander leaves (Coriandrum sativum)

The results are presented from the experimental picosecond nonlinear optical (NLO) studies of gold nanoparticles synthesised using coriander leaf (Coriandrum sativum) extract. Nanoparticles with an average size of ～30?nm (distribution of 5–70?nm) were synthesised according to the procedure reported by Narayanan et al. [Mater. Lett. 2008, 62, 4588–4591]. NLO studies were carried out using the Z-scan technique using 2?ps pulses near 800?nm. Open-aperture data suggested saturation absorption as the nonlinear absorption mechanism, whereas closed-aperture data suggested a positive nonlinearity. The magnitude of third-order nonlinearity was estimated to be (3.3?±?0.6)?×?10^?13?esu. A solvent contribution to the nonlinearity was also identified and estimated. A comparison is attempted with some recently reported NLO studies of similar gold nanostructures.     

Green synthesis of silver nanoparticles using flower extract of Malva sylvestris and investigation of their antibacterial activity

High‐quality colloidal silver nanoparticles (AgNP) were synthesised via a green approach by using hydroalcoholic extracts of Malva sylvestris. Silver nitrate was used as a substrate ion while the plant extract successfully played the role of reducing and stabilising agents. The synthesised nanoparticles were carefully characterised by using transmission electron microscopy, atomic‐force microscopy, energy dispersive X‐ray spectroscopy, Fourier transform infrared spectroscopy and UV–vis spectroscopy. The maximum absorption wavelengths of the colloidal solutions synthesised using 70 and 96% ethanol and 100% methanol, as extraction solvents, were 430, 485 and 504 nm, respectively. Interestingly, the size distribution of nanoparticles depended on the used solvent. The best particle size distribution belonged to the nanoparticles synthesised by 70% ethanol extract, which was 20–40 nm. The antibacterial activity of the synthesised nanoparticles was studied on Escherichia coli, Staphylococcus aureus and Streptococcus pyogenes using disk diffusion, minimum inhibitory concentrations and minimum bactericidal concentrations assays. The best antibacterial activity obtained for the AgNPs produced by using 96% ethanolic extract.Inspec keywords: silver, nanoparticles, nanofabrication, antibacterial activity, colloids, particle size, transmission electron microscopy, atomic force microscopy, X‐ray chemical analysis, Fourier transform spectra, infrared spectra, ultraviolet spectra, visible spectra, microorganisms, nanomedicine, biomedical materialsOther keywords: Green synthesis, flower extract, Malva sylvestris, antibacterial activity, high‐quality colloidal silver nanoparticles, hydroalcoholic extracts, plant extract, reducing agents, stabilising agents, transmission electron microscopy, atomic‐force microscopy, energy dispersive X‐ray spectroscopy, Fourier transform infrared spectroscopy, UV– vis spectroscopy, colloidal solutions, particle size distribution, Escherichia coli, Staphylococcus aureus, Streptococcus pyogenes, disk diffusion, minimum inhibitory concentrations, minimum bactericidal concentrations assays, ethanolic extract, size 430 nm, size 485 nm, size 504 nm, size 20 nm to 40 nm, Ag     

Rapid synthesis of highly stable silver nanoparticles and its application for colourimetric sensing of cysteine

A modified green approach for the synthesis of stable silver nanoparticles (AgNPs) using tea leaf extract is described. The method involves the reduction of silver salt by the polyphenols present in the green tea leaf extract and requires no additional capping/stabilising agents. Compared to other biogenic methods for the synthesis of AgNPs, the uniqueness of the approach described here lies in its simplicity, low-cost, and rapid synthesis rate; the reaction being completed within 10–15 min at room temperature. The reaction was carried out in alkaline medium without stirring and heating, and requires no special cleaning or drying of the glassware used. The synthesised AgNPs were characterised by UV–Vis spectroscopy and transmission electron microscopy (TEM). The results showed that AgNPs with a strong surface plasmon resonance peak around 410 nm and particle size in the 5–30 nm range were prepared. The synthesised AgNPs show excellent chemical stability for more than six months in aqueous solution. Additionally, we showed that the as-synthesised AgNPs can be used as highly selective colorimetric and optical sensors for the detection of cysteine. Thus, with a simple synthesis strategy, and enhanced stability, these green-tea-functionalised AgNPs have the potential for further applications as biosensors and antimicrobial agents.     

Synthesis and characterization of gold-conjugated <Emphasis Type="Italic">Backhousia citriodora</Emphasis> nanoparticles and their anticancer activity against MCF-7 breast and HepG2 liver cancer cell lines

Environmentally benign-synthesized gold nanoparticles (Au-NPs) have received substantial attention owing to their biomedical applications, particularly in cancer therapy. In the current study, Backhousia citriodora (B. citriodora) leaf extract was applied as a reducing agent for one-pot synthesis of controlled size Au-NPs. The effect of various parameters such as reaction time, pH, and B. citriodora leaf boiling time on the synthesis of Au-NPs was studied. The characterization of the Au-NPs synthesized at 15.0-min incubation time showed colour change because of the surface plasma resonance band around 530.0 nm. TEM photographs showed spherical morphologies with an average size of 8.40 ± 0.084 nm and zeta potential value was ? 29.74 mV, indicating stability of the nanoparticles. The biomedical properties of Au-NPs and B. citriodora leaf extract showed strong DPPH radical scavenging. The in vitro anticancer activity determined using MTT assay exhibited that Au-NPs showed a significant dose-dependent reduction in the viability of the MCF-7 breast cancer cell line and the HepG2 liver cancer cell line with IC₅₀ values of 116.65 and 108.21 µg, respectively.     

Synthesis of gold and silver nanoparticles using Mukia maderaspatna plant extract and its anticancer activity

The present investigation reveals the in vitro cytotoxic effect of the biosynthesised metal nanoparticles on the MCF 7 breast cancer cell lines. The gold and silver nanoparticles were synthesised through an environmentally admissible route using the Mukia Maderaspatna plant extract. Initially, the biomolecules present in the plant extract were analysed using phytochemical analysis. Further, these biomolecules reduce the metal ion solution resulting from the formation of metal nanoparticles. The reaction parameters were optimised to control the size of nanoparticles which were confirmed by UV visible spectroscopy. Various instrumental techniques such as Fourier transform‐infrared spectroscopy, high resolution transmission electron microscopy, energy dispersive X‐ray and scanning electron microscopy were employed to characterise the synthesised gold and silver nanoparticles. The synthesised gold and silver nanoparticles were found to be 20–50 nm and were of different shapes including spherical, triangle and hexagonal. MTT and dual staining assays were carried out with different concentrations (1, 10, 25, 50 and 100 µg/ml) of gold and silver nanoparticles. The results show that the nanoparticles exhibited significant cytotoxic effects with IC 50 value of 44.8 µg/g for gold nanoparticles and 51.3 µg/g for silver nanoparticles. The observations in this study show that this can be developed as a promising nanomaterial in pharmaceutical and healthcare sector.Inspec keywords: gold, silver, nanoparticles, nanofabrication, nanomedicine, biomedical materials, cancer, cellular biophysics, ultraviolet spectra, visible spectra, Fourier transform infrared spectra, transmission electron microscopy, X‐ray chemical analysis, scanning electron microscopyOther keywords: gold nanoparticle synthesis, silver nanoparticle synthesis, Mukia maderaspatna plant extract, anticancer activity, MCF 7 breast cancer cell line, biomolecule, phytochemical analysis, size 20 nm to 50 nm, healt hcare sector, pharmaceutical sector, nanomaterial, dual staining assay, MTT assay, scanning electron microscopy, energy dispersive X‐ray spectrocopy, high resolution transmission electron microscopy, Fourier transform‐infrared spectroscopy, instrumental technique, ultraviolet‐visible spectroscopy, metal nanoparticle formation, metal ion solution     

A novel approach for the biosynthesis of silver oxide nanoparticles using aqueous leaf extract of Callistemon lanceolatus (Myrtaceae) and their therapeutic potential

This study describes a novel biological route for the biosynthesis of silver oxide nanoparticles utilising the aqueous extract of Callistemon lanceolatus D.C. leaves. Formation of silver oxide nanoparticles was confirmed by UV–visible spectroscopy, Fourier transform infrared spectroscopy, scanning electron microscope–energy dispersive X-ray spectroscopy and X-ray diffraction spectroscopy analysis. The biologically synthesised silver oxide nanoparticles were found to be 3–30 nm in size with spherical and hexagonal shape by high-resolution transmission electron microscope analysis. Furthermore, the biogenic silver oxide nanoparticles demonstrated significant (p?in vitro antioxidant methods. These particles also exhibited significant (p?相似文献   

Solar photocatalytically active,engineered silver nanoparticle synthesis using aqueous extract of mesocarp of Cocos nucifera (Red Spicata Dwarf)

ABSTRACT

Silver nanoparticles synthesised using aqueous extract of Cocos nucifera (CN) mesocarp were evaluated for their photocatalytic activity under solar irradiation. The silver nanoparticles were synthesised by a green method of harnessing bioactive phytocomponents from the mesocarp of Cocos nucifera. Large-scale application of this process necessitates the manoeuvering of the process parameters for increasing the conversion of silver ions to nanoparticles. Process parameters influencing the morphological characteristics of silver nanoparticles such as precursor salt concentration and pH of the synthesis mixture were studied. The crystalline nanoparticles were characterised using UV-vis spectroscopy, XRD, FTIR, SEM and EDX analysis. CN extract and 5 mM silver nitrate solution at a ratio of 1:4 (v/v) in the synthesis mixture was found to be the optimum. Alkaline initial pH of the synthesis mixture was found to favour the synthesis of smaller sized monodispersed silver nanoparticles. Solar energy was harnessed for the photocatalytic degradation of Malachite green dye using silver nanoparticles obtained through the green synthesis method. Overall process aims at utilisation of naturally available resource for the synthesis of silver nanoparticles as well as the degradation of dyes using these nanoparticles, making it useful in the treatment of wastewater.     

Green synthesis of silver nanoparticles using hypericin-rich shoot cultures of Hypericum hookerianum and evaluation of anti-bacterial activities

The paper reports a green chemistry approach for the synthesis of silver nanoparticles (AgNPs) using hypericin-rich shoot cultures of Hypericum hookerianum as reducing agent. Normal green shoot cultures deficient in hypericin and red-pigmented shoot cultures rich in hypericin (3.01% DW) were raised in Murashige and Skoog nutrient medium containing 1.0 mg/L kinetin (KIN) and 0.2 mg/L naphthaleneacetic acid (NAA), respectively. Dried powder extracts of whole shoots were used for AgNPs formation. The effect of temperature on the formation of AgNPs is investigated. The nanoparticles obtained were characterised using UV–Vis spectroscopy, field emission scanning electron microscopy (FESEM), energy-dispersive X-ray (EDX) and X-ray diffraction (XRD) analyses. The UV–Vis spectra of AgNPs gave surface plasmon resonance (SPR) at 440 nm. The synthesised AgNPs were effective against different multidrug-resistant human pathogens such as Bacillus subtillis (Gram positive) and Pseudomonas aeruginosa (Gram negative) species. Further, the effect of hypericin concentration on anti-bacterial activity was investigated and was found to increase with increase in concentration.     

Green synthesis of silver nanoparticles using Nervalia zeylanica leaf extract and evaluation of their antioxidant,catalytic, and antimicrobial potentials

ABSTRACT

Here we report a simple, one-pot, inexpensive, and eco-friendly method for the synthesis of silver nanoparticles. The leaf extract of a medicinal plant Nervalia zeylanica was used as reducing and stabilizing agent for the synthesis of nanoparticles by microwave-assisted strategy. The nanoparticles show characteristic surface plasmon peak at 468?nm in UV–vis absorption spectrum. The involvement of phytochemicals in the reduction and stabilization of nanoparticles was confirmed by FTIR analysis. Using X-ray diffraction analysis, the crystalline nature of the nanoparticles was demonstrated. Transmission electron microscopic analysis shows that the nanoparticles were in spherical shape with average particle size of 34.2?nm. The antioxidant studies were performed by the 1,1-diphenyl-2-picryl hydrazyl method. The nanoparticles show excellent scavenging activities than the leaf extract. The IC₅₀ values of silver nanoparticles and the leaf extract, respectively, were 15.20 and 92.83?µg?mL^?1. The catalytic activities of synthesized nanoparticles were examined by using them in the reduction of organic dyes. The nanoparticles show excellent catalytic activities and follow pseudo-first-order kinetics. The antimicrobial activities of nanoparticles were analyzed by an agar well diffusion method against six microbial strains and found that the nanoparticles were highly toxic against all the tested microbial strains.     

Synthesis and characterization of silver nanoparticles and their antimicrobial efficacy

An efficient protocol for synthesis of silver nanoparticles (AgNPs) using the combination of aqueous extract of Tinospora cordifolia leaves and 5 mM silver nitrate (AgNO₃) solution was developed. This study revealed that bioactive compounds present in the extract function as stabilizing and capping agent for AgNPs. Scanning electron microscope and transmission electron microscope studies confirm the structure and surface morphology of the AgNPs. The size of synthesized AgNPs was in the range of 30–50 nm having spherical morphology. The crystalline nature of NPs was defined by the X-ray diffraction pattern. The AgNPs were found to be toxic against pathogenic bacteria such as Escherichia coli (ATCC 25922), Pseudomonas aeruginosa (ATCC 27853), and Staphylococcus aureus (ATCC 29213) and against plant pathogenic fungi Fusarium oxysporum (MTCC 8608) and Sclerotinia sclerotiorum (MTCC 8785). The use of AgNPs as antibacterial and antifungal agent is advantageous over other methods for control of pathogenic microorganisms, and it can be of great importance in developing novel drugs for curing many lethal diseases.     

Antifungal effect of green synthesised silver nanoparticles against Setosphaeria turcica

Green synthesis of silver nanoparticles (AgNPs) is an interesting issue of the nanoscience and nanotechnology due to their unique properties. In the present study, Ginkgo biloba L. leaf extract was used to synthesise AgNPs. The effects of quantity of leaves, concentration of Ag nitrate (AgNO₃), reaction temperature, and pH were studied to discover the optimal synthesis system. In addition, antifungal effect of AgNPs against Setosphaeria turcica was measured through inhibition zone method. The optimal biosynthesis system contained 15 g of leaf, 8 mM AgNO₃, and 80°C at pH 9.0. Under mentioned conditions, the resulting synthesised NPs were nearly spherical, with an average size of 14 nm. In tests, AgNPs synthesised at different pH resulted in different inhibition zones, diameters increased gradually at pH from 3.0 to 11.0, while antifungal effect reached maximum at 9.0. Results of this study offer a new approach for biological control plant pathogenic fungi, and it has potential application for screening novel fungistats with high efficiency and low toxicity.Inspec keywords: antibacterial activity, silver, nanoparticles, nanobiotechnology, pHOther keywords: antifungal effect, green synthesised silver nanoparticles, Setosphaeria turcica, nanoscience, nanotechnology, Ginkgo biloba L. leaf extract, reaction temperature, pH, inhibition zone method, inhibition zones, mass 15 g, temperature 80 degC, size 14 nm, Ag     

Enhanced Stability,Conductance, and Catalytic Activity of Gold Nanoparticles via Oxidative Dissolution by KMnO4

The present paper reports the oxidative etching of Au nanospheres by an oxidant, KMnO₄, which resulted in the formation of new particles of different reduced sizes from single starting nanoparticles. The significant blue-shifting (536 → 527 nm) of the surface plasmon band for Au nanospheres was observed due to their size alterations after oxidative dissolution of Au⁰ to Au⁺³. This was supported by the cyclic voltammetry studies, which revealed an anodic peak at ?0.90 V in agreement with the standard electrode potential of Au⁰/Au⁺³ (?0.96 V). Dynamic light scattering (DLS) analysis showed that the hydrodynamic diameter of Au nanospheres (～41 nm) was decreased from ～26 to 4 nm as a function of KMnO₄ concentration, as further evidenced by TEM. This oxidation-driven process resulted in colloids with higher zeta potential, conductance, and enhanced catalytic activity (～2 times) than their bare nanoparticles for the reduction of p-nitrophenol to p-aminophenol attributed to the higher surface area-to-volume ratio.     

Solventless synthesis of a Schiff base that forms highly fluorescent organic nanoparticles exhibiting aggregation-induced emission in aqueous media

A highly fluorescent solid state Schiff base compound (DBD) was synthesised using a green, solventless and fast approach in 30 sec. DBD shows almost no emission in THF solution, while it emits strong fluorescence in both dispersed nano-aggregates in the solution and as a powder, through a phenomenon known as aggregation-induced emission. Organic nanoparticles of DBD were prepared in aqueous solution using the nanoreprecipitation method with and without stabilizers. The nanoparticles exhibited strong, blue emission when the non-ionic surfactant, like triton X-100, was used as a stabilizer, and strong green emission when no surfactant or the cationic surfactant, like CTAB as a stabilizer was used. Using atomic force microscopy and dynamic light scattering, the sizes of the nanoparticles were found to be around 75 nm when prepared without surfactant, 50 nm when prepared using triton X-100, and 30 40 nm when prepared using CTAB. DBD nanoparticles show an emission maximum at 527 nm (pure green) in the cases of CTAB and no surfactant, while 400 nm emission is observed when triton X-100 is used. Finally, for practical applications, the new type of highly fluorescent organic nanoparticles (DBD) were chosen for on/off fluorescence switching nano sensor for detecting organic vapour.     

Microwave-assisted biosynthesis of gold–silver alloy nanoparticles and determination of their Au/Ag ratio by atomic absorption spectroscopy

In this investigation, our research interest focused on the microwave-assisted biosynthesis of Au–Ag alloy nanoparticles and their purification and characterisation. Dextrose and the ethanol extract of black tea (Camellia sinensis) were used as natural reducing agents for preparing Au–Ag alloy nanoparticles under microwave irradiation. The synthesised alloy nanoparticles were further purified with the agarose gel electrophoresis technique. The characterisation of the separated nanoparticles as particle shapes, size and their chemical composition was studied with UV–Vis spectroscopy, transmission electron microscopy and atomic absorption spectroscopy. Purified Ag–Au alloy nanoparticles were spherical in the size range of ≤200?nm, and possessed an average size of 92?nm. The results of atomic absorption spectroscopy show the presence of both metals (gold and silver) in the purified bimetal nanoparticles at a molar ratio of 3?:?1. Although we selected the Au³⁺/Ag⁺ mixture solution with a molar ratio of 1/1, we did not obtain Au–Ag alloy nanoparticles with the same portion. In the further investigation using resolution IV 2^(4?1) fractional factorial design, we established that the final concentrations of glucose and plant extract should be considered the main significant parameters affecting the Ag/Au ratio in the Ag–Au alloy nanoparticles.     

Potato extract as reducing agent and stabiliser in a facile green one-step synthesis of ZnO nanoparticles

A facile green recipe was developed to synthesise highly pure, safe and durable zinc oxide nanoparticles (ZnO Nps) using homemade starch-rich potato extract. The ZnO Nps were synthesised using zinc nitrate and potato extract, and the whole reaction is carried out for 30 min at 80 °C. In the synthesis, starch-rich potato extract acted as the reducing agent and as a stabilising layer on freshly formed ZnO Nps. Hexagonal (wurtzite) shaped ZnO Nps with size about 20 ± 1.2 nm were synthesised and characterised using X-ray diffraction, transition electron microscope and scanning microscopy analyses. Fourier transform infrared spectral analysis indicated that highly pure ZnO nanopowders were obtained at higher temperatures. The use of environmentally benign and renewable material as the respective reducing and protecting agents, starch-rich potato extract, as well as a gentle solvent medium (H₂O), offered a simple and quite efficient procedure for the synthesis of ZnO Nps in neutral medium with promising potential for biological and biomedical applications.     

Removal of toxic contaminants from water by sustainable green synthesised non‐toxic silver nanoparticles

The study describes the synthesis of silver nanoparticles using 21 different plant extracts having medicinal properties. Molecular ultraviolet‐visible spectroscopy shows that the λ _max of nanoparticles synthesised by different plant extracts varied and ranged between 400 and 468 nm. The ultraviolet results revealed that although synthesis of nanoparticles occurred by all plant extracts successfully, their size varies, this was further confirmed by differential light scattering. The synthesised nanoparticles were investigated for their antimicrobial properties. The most promising silver nanoparticles Ocimum sanctum and Artemisia annua assisted were further characterised using transmission electron microscopy and energy dispersive X‐ray spectroscopy (EDX). EDX data confirms that synthesised nanoparticles are highly pure. Further these two plant assisted nanoparticles were studied for chemocatalytic and adsorptive properties. The silver nanoparticles from Ocimum sanctum can catalyse the reduction of 4‐nitrophenol (63%) within 20 min in the presence of NaBH₄, whereas Artemisia annua assisted silver nanoparticles did not show significant chemocatalytic activity. Both the promising nanoparticles can efficiently adsorb textile dyes from aqueous solutions. These synthesised nanoparticles were also exploited to remove microbial and other contaminants from Yamuna River water. The nanoparticles show excellent antimicrobial properties and can be reused repeatedly.Inspec keywords: antibacterial activity, nanofabrication, silver, dyes, light scattering, visible spectra, microorganisms, X‐ray diffraction, transmission electron microscopy, X‐ray chemical analysis, catalysis, nanoparticles, ultraviolet spectra, adsorption, reduction (chemical)Other keywords: sustainable green synthesised nontoxic silver nanoparticles, silver nitrate, molecular ultraviolet–visible spectroscopy, plant assisted nanoparticles, plant extracts, Ocimum sanctum, Artemisia annua, E. coli, C. albicans, plasmon absorbance, differential light scattering, energy dispersive X‐ray spectroscopy, 4‐nitrophenol, chemocatalytic activity, Yamuna River water, antimicrobial properties, time 20.0 min, time 5.0 min to 240.0 hour, size 1.0 nm to 5.0 nm, size 5.0 nm to 20.0 nm, wavelength 400.0 nm to 468.0 nm, NaBH₄ , Ag     

Characterization of phyto-nanoparticles from Ficus krishnae for their antibacterial and anticancer activities

Background: Ovarian cancer is deadliest of fifth leading cause of death in women worldwide. This is due to advanced-stage disease rate associated with the development of chemoresistance. Hence, the current study emphasizes the process of synthesis of silver nanoparticles (AgNPs) from green chemistry method. Ficus krishnae is a perennial plant, native to India, used in folklore medicine to treat various diseases.

Objective: For the development of reliable, ecofriendly, less expensive process for the synthesis of AgNPs against bacterial and ovarian cancer.

Methodology: The synthesis of silver nanoparticles from stem bark of Ficus krishnae was carried out. The synthesized nanoparticles are subjected by UV-Vis spectrophotometer, scanning electron microscopy (SEM), X-ray diffraction (XRD) analysis and FTIR analysis. The antibacterial efficacy also determined by disc diffusion method, MIC, CFU and growth curve. In vitro cytotoxicity effect of aqueous extract and AgFK nanoparticle in ovarian cancer cell line by MTT assay was performed.

Results: The formation of AgNPs was confirmed by UV-VIS spectroscopic absorbance shown that peak at 435?nm. XRD photograph has indicated the face-centered cubic structure of the synthesized AgNPs. SEM study demonstrated that the size from 160 to 260?nm with interparticle distance, whereas shape is spherical. The particle size were ranging from 15 to 28?nm determined by XRD pattern. The antibacterial and cytotoxicity activity of this nanoparticle has showed a potential activity when compared with standards.

Conclusion: The present study confirms that the biosynthesized AgNPs from Ficus krishnae stem bark extract have a great affiance as antibacterial and anticancer agent.