Showed Surface Plasmon Resonance Research Articles

Green Synthesis and characterization of Lead Oxide Nanoparticles using Piper Betle leaf

Lead oxide nanoparticles were synthesized by using cost effective and eco friendly green method assisted by piper betle leaf extract. The UV absorption spectrophotometer analysis of leaf extract and metal compounds showed absorbance spectra in the range 300-400 nm. The UV-Vis spectroscopy shows Surface Plasmon resonance of PbO nanoparticles at 320 nm indicating that the particles are poly dispersed. The FT-IR measurements were carried out to identify the formation of lead oxide nanoparticles and possible molecules such as OH, C=C, C=O and aromatic compounds. The FT-IR analysis played a pivoted role in displaying the nanoparticles which showed strong absorbance in the range 518-600 cm-1 for lead oxide nanoparticles. The diffraction peaks and planes of ions are indexed. From the ‘X’ ray diffraction analysis, the size of the lead oxide nanoparticles is 70 nm as calculated by Debye scherrer’s equation. The size, shape and structure of nanoparticles were also analyzed by Scanning electron microscope showing tetragonal shape of nanoparticles aggregation. This green synthesis method has many advantages over the chemical method because it reduces the use of toxic metals in the synthesis process.

Influences of Plasma Plume Length on Structural, Optical and Dye Degradation Properties of Citrate-Stabilized Silver Nanoparticles Synthesized by Plasma-Assisted Reduction.

Citrate-capped silver nanoparticles (Ag@Cit NPs) were synthesized by a simple plasma-assisted reduction method. Homogenous colloidal Ag@Cit NPs solutions were produced by treating a -trisodium citrate-deionized water with an atmospheric-pressure argon plasma jet. The plasma-synthesized Ag@Cit NPs exhibited quasi-spherical shape with an average particle diameter of about 5.9−7.5 nm, and their absorption spectra showed surface plasmon resonance peaks at approximately 406 nm. The amount of Ag@Cit NPs increased in a plasma exposure duration-dependent manner. Plasma synthesis of Ag@Cit NPs was more effective in the 8.5 cm plume jet than in the shorter and longer plume jets. A larger amount of Ag@Cit NPs were produced from the 8.5 cm plume jet with a higher pH and a larger number of aqua electrons, indicating that the synergetic effect between plasma electrons and citrate plays an important role in the plasma synthesis of Ag@Cit NPs. Plasma-assisted citrate reduction facilitates the synthesis of Ag@Cit NPs, and citrate-capped nanoparticles are stabilized in an aqueous solution due to their repulsive force. Next, we demonstrated that plasma-synthesized Ag@Cit NPs exhibited a significant degradation of methylene blue dye.

Chitosan and cetyltrimethylammonium bromide capped Iridium-silver bimetallic nanoparticles: A comparative study

Cetyltrimethylammonium bromide (CTAB) and chitosan capped iridium-silver nanoparticles (Ir-AgNPs) were synthesized by using seedless co-reduction of metal salts precursors with sodium borohydride. CTAB and chitosan capped Ir-Ag shows surface Plasmon resonance (SPR) band at 420 nm and 430 nm, respectively. Chitosan + Ag+ + Ir3+ reaction mixture reduced much faster than that of CTAB + Ag+ + Ir3+ with NaBH4. Average Brunauer-Emmett-Teller (BET) surface area, particle size, cumulative pore size, cumulative pore volume were found to be 49.07 m2/g, 2.77 nm, 8.10 nm, 0.19 cc/g and 41.84 m2/g, 3.25 nm, 7.85 nm, 0.16 cc/g, respectively, for CTAB and chitosan capped Ir-AgNPs. The CTAB-Ir-AgNPs exhibit better stability in the wide range of pH and temperature for ca. several months. SEM, TEM, EDX, XRD, XPS, and FTIR were used to analyze the surface morphology, size, elemental composition, crystalline nature, oxidation states of metals and functional groups capping action of as-prepared Ir-AgNPs.

Comparative study of antifungal activity of two preparations of green silver nanoparticles from Portulaca oleracea extract

The green silver nanoparticles (green AgNPs) exhibit an exceptional antimicrobial property against different microbes, including bacteria and fungi. The current study aimed to compare the antifungal activities of both the crude aqueous extract of Portulaca oleracea or different preparations of green AgNPs biosynthesized by mixing that aqueous extract with silver nitrate (AgNO3). Two preparations of the green AgNPs were synthesized either by mixing the aqueous extract of P. oleraceawith silver nitrate (AgNO3) (normal AgNPs) or either irradiation of the AgNPs, previously prepared, under 60Co γ-ray using chitosan (gamma-irradiated AgNPs). Characterization of different AgNPs were tested by Zeta potential analyzer, Ultraviolet (UV) Visible Spectroscopy, and Fourier-Transform Infrared (FTIR) spectrometry. Three different plant pathogenic fungi were tested, Curvularia spicifera, Macrophomina phaseolina, and Bipolaris sp. The antifungal activities were evaluated by Transmission Electron Microscope (TEM) for either the crude aqueous extract of P. oleracea at three doses (25%, 50%, and 100%) or the newly biosynthesized AgNPs, normal or gamma-irradiated. With a few exceptions, the comparative analysis revealed that the irradiated green AgNPs at all three concentrations showed a relatively stronger antifungal effect than the normal AgNPs against all the three selected fungal strains. UV–visible spectroscopy of both preparations showed surface plasmon resonance at 421 nm. TEM results showed that both AgNPs were aggregated and characterized by a unique spherical shape, however, the gamma-irradiated AgNPs were smaller than the non-irradiated AgNPs (0.007–0.026 µM vs. 0.009–0.086 µM). TEM photographs of the fungal strains treated with the two AgNPs preparations showed flaccid structures, condensed hyphae, and shrunken surface compared with control cells. The data suggested that the biosynthesized P. oleracea AgNPs have antifungal properties against C. spicifera, M. phaseolina, and Bipolaris sp. These AgNPs may be considered a fungicide to protect different plants against phytopathogenic fungi.

Synthesis of Silver Nanoparticles Using Dichloromethane Extract of Chrysanthemum cinerariaefolium and Its Bioactivity

Common methods of synthesizing metallic nanoparticles are chemical and physical. However, they are expensive and use toxic chemicals. Green synthesis is less costly and safer hence a potential alternative. Silver nanoparticles (Ag NPs) were synthesized using dichloromethane extract of Chrysanthemum cinerariaefolium and colour change from pale green to dark brown was observed. Scanning Electron Microscopy (SEM) images were faceted and others formed clusters. Transmission Electron Microscopy (TEM) images were spherical with an average size of 22.8± 17.5 nm. EDX analysis showed the nanoparticles had percentage abundance of 67.26%. Fourier-transform Infrared Spectroscopy (FTIR) analysis showed absorption bands at 3489.59 cm-1, 3217.80 cm-1, 2384.74 cm-1 , 1633.05 cm-1, 1405.08 cm-1, 1109.32 cm-1 and 505.93 cm-1. The UV-Vis analysis showed Surface Plasmon Resonance (SPR) peak at 434 nm. The nanoparticles were more active on P. aeruginosa with an MIC of 15 µg/ml while the cytotoxicity assay showed Ag NPs had an MIC of 33.33 µg/ml hence were noncytotoxic against Vero cells.

Gold Nanoparticles; Synthesis, Characterization and Comparative Studies of Their Antimicrobial Activities

Gold nanoparticles of various morphologies have been synthesized using different synthetic approaches. Sonochemical synthesis results in the formation of 25 nm sized gold nano discs and 30 nm sized polyhedral structures with surface area of 179.5 m2/g and 150.5 m2/g respectively[1]. The UV-Visible spectrum shows the SPR peaks due to in plane and out of plane excitation modes. Microemulsion synthesis using Tergitol NP-9 surfactant resulted in the production of hexagonal gold nanoparticles (avg. size: 20 nm) at 0.05 M HAuCl4 (aq) and spherical morphologies with an average size of 25 nm and 15 nm at molar concentrations of 0.04 M and 0.03 M HAuCl4 (aq) respectively[2]. Gold nanoparticles show the surface plasmon resonance peaks at 540 nm and 580 nm along with peaks corresponding to higher order plasmon resonance modes at shorter wavelengths. The surface area was found to increase with decrease in particle size. An ecofriendly synthetic route was also employed to synthesize gold nanoparticles using candida albicans fungal cell free extract[3]. Gold nanocrystals of 5 nm have been obtained with specific surface area of 18.9 m2/g. The encapsulation of gold nanoparticle by biomolecules of the cell free extract was confirmed by FTIR and TGA studies. Gold nanoparticle show surface plasmon resonance (SPR) peak at 540 nm. Gold nanoparticles have been tested for antimicrobial activity against fungal and bacterial species. Gold nano discs displayed higher antimicrobial action against fungus candida albicans as compared to gold polyhedral structures by inhibiting H+-ATPase activity. Biosynthesized gold nanoparticles showed good antimicrobial activity against Staphylococcus aureus and Escherichia coli. However, Escherichia coli, a gram-negative bacterium was found to be more susceptible to gold nanoparticles as compared to Staphylococcus aureus, a gram-positive bacterium. The microemulsion synthesized gold nanoparticles were tested against Candida albicans both alone and in combination with fluconazole. The gold nanoparticles in combination with fluconazole showed maximum inhibition and the antifungal activity increased with decrease in particle size.

Structural, morphological and electrical properties of PVA/Au nanocomposite films

In the present work, the preparation of nanocomposite films of poly(vinyl alcohol) (PVA) embedded with in situ generated gold nanoparticles (AuNPs) by UV-B irradiation is reported. The formation of AuNPs showed surface Plasmon resonance (SPR) peak in the wavelength range of 532–558 nm, confirmed by UV–Visible (UV–Vis) spectroscopy. X-ray diffraction (XRD) analysis confirmed the crystalline nature of the AuNPs with FCC crystal structure. FT-IR analysis suggests the interaction between AuNPs and PVA through intra/intermolecular hydrogen bonding. Surface morphology was found by scanning electron microscopic (SEM) analysis. The as-prepared PVA/Au nanocomposite films showed enhanced electrical conductivity over pure PVA.

Optimization for synthesis of silver nanoparticles through response surface methodology using leaf extract of Boswellia sacra and its application in antimicrobial activity.

In the present work, leaf extract of Boswellia sacra was used as reductant for synthesis of silver nanoparticles (AgNPs). The variables such as volume of Boswellia sacra leaf extract (1%), volume of silver nitrate (1mM), and temperature were optimized by response surface methodology via Box-Behnken design for the synthesis of AgNPs. Design-Expert software generated the optimum conditions for the highest yield of silver nanoparticles as 8mL of 1mM AgNO3, 8mL of 1% Boswellia sacra leaf extract, and temperature = 55°C. The formed AgNPs were isolated and purified by centrifugation process using ethanol/ distilled water. AgNPs were characterized using FTIR, SEM, TEM, EDX, and XRD. AgNPs showed surface plasmon resonance absorption band at 422nm. XRD pattern indicated the crystalline nature of the particles (diameter 11.17 to 37.50nm) with face-centered cubic structure. SEM and TEM images highlighted the formation of spherical AgNPs. The energy dispersive spectroscopic spectrum confirmed the presence of elemental silver. The microbial activity of AgNPs was evaluated against bacteria and fungi. Synthesized AgNPs were very effective against Gram-positive E. coli bacterial strains and fungal strains (Penicillium chrysogenum).

The regularities of the Mentha piperita L. extract mediated synthesis of gold nanoparticles with a response in the infrared range

Here we report on the application of Mentha piperita L. extract mediated synthesis of gold nanoparticles (AuNPs) with a response in the infrared range. Chromatographic studies showed the extract of M. piperita contains secondary metabolites typically acting as reducing and stabilizing agents. To shed light on the kinetic regularities of the phytosynthesis, we examined the formation of Au nanocolloids in situ considering the impact of the content of reagents: the extract (0.25 mg/ml of dry matter) and HAuCl4 (0.025–0.975 mM) were investigated in the time range 1–75 min. The formation of non-spherical AuNPs is confirmed by TEM and UV–Vis characterization of nanocolloids. UV–Vis spectroscopy showed surface plasmon resonance peaks at 534 and > 900 nm drifting into the infrared range with time and composition of reacting mixtures. The sizes of AuNPs according to the protocol varied from 10 to near 200 nm. TEM showed pseudo-spherical, triangular, and hexagonal AuNPs. Non-ideal surface relief by AFM data for large triangular and hexagonal AuNPs and structural imperfections from HRTEM studies are demonstrated. Kinetic studies showed S-shaped kinetic curves for the reaction of HAuCl4 and the plant extract. All effective constants found for the process of NPs forming can be explained by the more intense formation of large AuNPs and by the formation of NPs of a different shape with a different absorption spectrum at the same time.

Starch-Capped AgNPs' as Potential Cytotoxic Agents against Prostate Cancer Cells.

One of the major therapeutic approaches of prostate cancer (PC) is androgen deprivation therapy (ADT), but patients develop resistance within 2–3 years, making the development of new therapeutic approaches of great importance. Silver nanoparticles (AgNPs) synthesized through green approaches have been studied as anticancer agents because of their physical-chemical properties. This study explored the cytotoxic capacity of starch-capped AgNPs, synthesized through green methods, in LNCaP and in PC-3 cells, a hormonal-sensitive and hormone-resistant PC cell line, respectively. These AgNPs were synthesized in a microwave pressurized synthesizer and characterized by ultraviolet-visible (UV-Vis) spectroscopy, transmission electron microscopy (TEM), and energy-dispersive X-ray spectroscopy (EDX). Their cytotoxicity was assessed regarding their ability to alter morphological aspect (optical microscopy), induce damage in cytoplasmic membrane (Trypan Blue Assay), mitochondria (WST-1 assay), cellular proliferation (BrdU assay), and cell cycle (Propidium iodide and flow-cytometry). AgNPs showed surface plasmon resonance (SPR) of approximately 408 nm and average size of 3 nm. The starch-capped AgNPs successfully induced damage in cytoplasmic membrane and mitochondria, at concentrations equal and above 20 ppm. These damages lead to cell cycle arrest in G0/G1 and G2/M, blockage of proliferation and death in LNCaP and PC-3 cells, respectively. This data shows these AgNPs’ potential as anticancer agents for the different stages of PC.

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

PurposeThe present study investigates the phytosynthesis of silver nanoparticles (AgNPs) using Perilla frutescens leaf extract, which acts as a reducing agent for the conversion of silver ions (Ag+) into AgNPs. P. frutescens leaf synthesized AgNPs (PF@AgNPs) were evaluated for biomedical properties including antibacterial, antioxidant and anticancer activities.Materials and MethodsPF@AgNPs were synthesized using P. frutescens leaf extract and silver nitrate solution. The morphology and physical properties of PF@AgNPs were studied by spectroscopic techniques including, UV-Vis, FTIR, TEM, XRD, DLS, and TGA. Antibacterial activity of PF@AgNPs was evaluated by disk diffusion assay. Antioxidant activity of PF@AgNPs was checked by 2.2-diphenyl-1-picrylhydrazyl (DPPH), and 2.2ʹ-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) free radical scavenging assays. Anticancer activity of PF@AgNPs was checked by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay. Cytotoxic effects of PF@AgNPs on most susceptible cancer cell lines were observed by phase contrast microscopy.ResultsPF@AgNPs showed surface plasmon resonance peak at 461 nm. XRD pattern showed that the PF@AgNPs were face-centered cubic crystals with a mean size of 25.71 nm. TEM analysis revealed the different shapes (spherical, rhombic, triangle, and rod) of PF@AgNPs. Zeta potential value (−25.83 mV) indicated that PF@AgNPs were long-term stable and not agglomerated. A low polydispersity index value (0.389) indicated the monodispersity of PF@AgNPs. TGA revealed the high thermal stability of PF@AgNPs. PF@AgNPs exhibited maximum inhibition against Escherichia coli, followed by Bacillus subtilis and Staphylococcus aureus. PF@AgNPs showed maximum inhibition of 68.02 and 62.93% against DPPH and ABTS-free radicals, respectively. PF@AgNPs showed significant anticancer activity against human colon cancer (COLO205) and prostate adenocarcinoma (LNCaP). PF@AgNPs exhibited apoptotic effects on LNCaP cells including cell shrinkage, membrane blebbing, chromatin condensation, fragmentation of nuclei, and formation of apoptotic bodies.ConclusionThe present study reports the successful synthesis of PF@AgNPs using P. frutescens leaf extract. The synthesized PF@AgNPs are FCC crystals, monodispersed, long-term stable, and non-agglomerated. The observed antibacterial, antioxidant, and anticancer activities demonstrate the potential biomedical applications of PF@AgNPs.

The Development of Antibiotics Based on Nanostructured Manganese Oxide; Understanding Mechanism from Fundamental Aspects to Application.

The emergence of bacterial resistance to currently available antibiotics emphasized the urgent need for new antibacterial agents. Nanotechnology-based approaches are substantially contributing to the development of effective and better-formulated antibiotics. Here, we report the synthesis of stable manganese oxide nanostructures (MnO NS) by a facile, one-step, microwave-assisted method. Asprepared MnO NS were thoroughly characterized by atomic force microscopy (AFM), field emission scanning electron microscopy (FESEM), dynamic light scattering (DLS), UV-Visible spectroscopy and X-ray powder diffraction (XRD). UV-Visible spectra give a sharp absorption peak at a maximum wavelength of 430 nm showed surface plasmon resonance (SPR). X-ray diffraction (XRD) profile demonstrated pure phase and crystalline nature of nanostructures. Morphological investigations by a scanning electron microscope showed good dispersity with spherical particles possessing a size range between 10-100 nm. Atomic force microscope data exhibited that the average size of MnO NS can be controlled between 25 nm to 150 nm by a three-fold increment in the amount of stabilizer (o-phenylenediamine). Antimicrobial activity of MnO NS on both gram-positive (Bacillus subtilis) and gram-negative (Escherichia coli) bacterial strains showed that prepared nanostructures were effective against microorganisms. Further, this antibacterial activity was found to be dependent on nanoparticles (NPs) size and bacterial species. These were more effective against Bacillus subtilis (B. subtilis) as compared to Escherichia coli (E. coli). Considering the results together, this study paves the way for the formulation of similar nanostructures as effective antibiotics to kill other pathogens by a more biocompatible platform. This is the first report to synthesize the MnO NS by green approach and its antibacterial application.

Synthesis of gold nanoparticles using novel Eucalyptus tereticornis and their in-vitro antibacterial, antioxidant and anticancer studies

Development of biologically inspired experimental procedures for synthesis of nanoparticles (NPs) is an important branch of nanotechnology. Synthesis of NPs which are nontoxic, eco-friendly, inexpensive and having potential medicinal properties is challenging. In present study, gold NPs were produced from Eucalyptus tereticornis leaf extract (Et-AuNPs). The Et-AuNPs were confirmed using UV–Vis absorption study which shows surface plasmon resonance peak at 569 nm. Various characteristics of Et-AuNPs were demonstrated by characterisation techniques such as scanning electron microscopy, transmission electron microscopy, x-ray diffraction and energy dispersive spectroscopy. It is found that prepared Et-AuNPs are well dispersed and spherical in shape. Significant anticancer effect on MCF-7 cell lines was observed in dose-dependent manner having IC50 value of 52.0 μg ml−1. Further antibacterial studies were carried out by disc-diffusion method, which revealed potential antibacterial activity of Et-AuNPs against pathogenic bacterial strains. Et-AuNPs also exhibited promising free radical scavenging efficiency performed by DPPH assay with IC50 values of 62.6 μg ml−1. The results suggest that green synthesised AuNPs can be exploited for clinical as well as pharmaceutical activities using nanomedicine approach in near future.

Biosynthesis Copper Nanoparticles using Blumea balsamifera Leaf Extracts: Characterization of its Antioxidant and Cytotoxicity Activities

A facile and green route of copper nanoparticles (Cu NPs) was synthesized using Blumea balsamifera leaf extracts, the optical, morphology and elemental analysis were characterized by UV–Vis spectrophotometer, scanning electron microscope (SEM) and energy dispersive x-ray spectroscopy (EDX). UV–Vis absorption showed surface plasmon resonance (SPR) peak at 540 nm which confirms the formation of Cu NPs. SEM analysis exhibits spherical shape with size 30-55 nm and EDX results revealed that only Cu metal was present in Cu NPs. The phytochemical constituents of Cu NPs and Blumea balsamifera leaf extracts were analyzed by gas chromatography-mass spectrometry (GC-MS). The presence of bioactive phytochemical constituents in the ethyl acetate extracts of B. balsamifera and with Cu NPs was identified by GC-MS. Results of antioxidant activity showed that increase in concentration of Cu NPs could further increases the radical scavenging activity up to 69 % at 100 µg/ml. In addition, the degree of lethality was directly correlated with the concentration of green synthesized Cu NPs indicates the cytotoxicity activity. The present study revealed that the phytochemical active compounds present in B. balsamifera act as bioreductant in the formation of Cu NPs, thus pave the way to its effective application in biomedical, antibacterial and nano-drug delivery systems.

Covalently Conjugated Gold-Porphyrin Nanostructures.

Gold nanoparticles show important electronic and optical properties, owing to their size, shape, and electronic structures. Indeed, gold nanoparticles containing no more than 30–40 atoms are only luminescent, while nanometer-sized gold nanoparticles only show surface plasmon resonance. Therefore, it appears that gold nanoparticles can alternatively be luminescent or plasmonic and this represents a severe restriction for their use as optical material. The aim of our study was the fabrication of nanoscale assembly of Au nanoparticles with bi-functional porphyrin molecules that work as bridges between different gold nanoparticles. This functional architecture not only exhibits a strong surface plasmon, due to the Au nanoparticles, but also a strong luminescence signal due to porphyrin molecules, thus, behaving as an artificial organized plasmonic and fluorescent network. Mutual Au nanoparticles–porphyrin interactions tune the Au network size whose dimension can easily be read out, being the position of the surface plasmon resonance strongly indicative of this size. The present system can be used for all the applications requiring plasmonic and luminescent emitters.

Biogenic synthesis of mono dispersed Co/CoO nanoparticles using Syzygium cumini leaves for catalytic application

Copper and copper oxide nanoparticles (Co/CoO NPs) were synthesized by a green approach using Syzygium cumini leaf extract. The formation of synthesized Co/CoO NPs was monitored by using UV–Visible spectroscopy which shows surface plasmon resonance (SPR) at 380 nm. The parameters affecting the particle size or yield of Co/CoO NPs including pH, temperature, reaction time, and concentration of salt also has been studied. The performance or efficiency of catalysts has been investigated by the degradation of 4-nitrophenol (4-NP) and methylene blue (MB) in the presence of sodium borohydride. The kinetic studies displayed that Co/CoO NPs obeyed pseudo-first-order for catalysis of selected contaminants.

Facile, Low-Cost and Rapid Phytosynthesis of Stable and Eco-friendly Silver Nanoparticles Using Boerhavia elegans (Choisy) and Study of Their Antimicrobial Activities

In recent years, the application of bioengineering methods has attracted special focus because of simplicity, low cost, high efficiency, non-toxicity, and environmental compatibility. The present study is the first report of biosynthesis of silver nanoparticles (SNPs) using Boerhavia elegans (choisy). 2 mL of extract was added to 4 mL of AgNO3 with concentration of 1 mM. In order to obtain nanoparticles (NPs) with uniform shape and size, factors affecting the synthesis of NPs, such as: pH of reaction, volume of extract, concentration of silver (I), temperature and time of reaction were evaluated and optimized using UV–Vis spectrophotometry. To characterize the NPs, Transmission Electron Microscopy (TEM) and Power X-ray Diffraction (PXRD) and Fourier-Transformed Infrared Spectroscopy techniques were used. Finally, the antimicrobial activities of SNPs were investigated on four and two pathogenic bacteria and fungi using disc diffusion method. The SNPs showed Surface Plasmon Resonance centered at 405 nm. The PXRD pattern and TEM analysis revealed spherical, stable, and uniform SNPs with the average particle size of 15 nm. The antimicrobial activity of the synthesized SNPs showed a significant microbial effect on all clinical isolates especially, bacteria and fungi. These results suggest that such stable and uniform SNPs can be synthesized rapidly and simply for clinical as well as pharmaceutical applications.

Radiation-induced synthesis of tween 80 stabilized silver nanoparticles for antibacterial applications

Recently, Silver nanoparticles (AgNPs) have become widely applied nanomaterial in human contacting areas such as cosmetics, food and medicine due to their antibacterial property. On the other hand, surfactants are essential ingredient of several industrial and consumer formulations. Based on these important applications, the current research was aimed to carry out the synthesis and characterization of Tween 80 capped silver nanoparticles (T80-AgNPs) using gamma radiation reduction method. Characterization of T80-AgNPs was occurred by using UV–Vis, XRD, FTIR and TEM techniques. UV–Visible spectra showed surface plasmon resonance (SPR) peak in the range of 420 nm signifying the synthesis of colloidal AgNPs. TEM confirmed the formation of spherical and uniformly distributed AgNPs with average size of 18 nm. XRD analysis illustrated the formation of pure crystalline AgNPs. The FTIR analysis provides evidence for the stabilization of AgNPs by Tween 80. The synthesized T80-AgNPs were evaluated for antibacterial activity against both Escherichia coli (E. coli) as gram negative (G –ve) bacteria and Staphylococcus aureus (S. aureus) as gram positive (G + ve) bacteria and anti-biofilm activity to P. aeruginosa. The results show that T80-AgNPs exhibits excellent antibacterial and antibiofilm activities.

English

In this study, biosynthesis of silver nanoparticles (AgNPs) and its toxicity were investigated. Different functional groups responsible for adsorption, morphology and absorption of the nanoparticle were characterized using UV-Vis, Fourier transmission infrared spectroscopy (FTIR), and scanning electron microscope (SEM) analyses, respectively. The toxicity of orally administered Azadirachta indica AgNPs was assessed in Swiss albino rats. Sub-acute toxicity was determined in daily dosages from 30-0.3 mg/kg body weight for 28 days. Chronic toxicity was determined in two dosages 30 and 10 mg/kg body weight for 180 days. Control groups were included and were administered with distilled water. The UV-Vis spectroscopy showed surface plasmon resonance of 430 nm for the silver nanoparticle. The FTIR spectrum showed primary-N-H bond and secondary-C-N amides. The nanoparticles synthesized were 45 nm average sizes. There were no significant differences (P>0.05) observed between the packed cell volume (PCV), animals body weight of the control and treatment groups in sub-acute and chronic toxicity. Portal hepatitis in the liver at the 30 mg/kg b. wt was noted. Hence, histopathology examinations confirmed the liver damage noted in clinical biochemistry. Kidneys histological organization appeared normal generally with glomeruli and tubules visible. Our results demonstrate that A. indica silver nanoformulation may be safe at daily dosage of up-to 10 mg/kg b. wt. However, it indicates that the A. indica silver nanoformulation on daily use at 30 mg/kg may lead to liver damage.   Key words: Silver nanoparticles, toxicity, Azadirachta indica, rats. &nbsp

GREEN SYNTHESIS, ANTIMICROBIAL AND ANTICANCER ACTIVITIES OF AgNPs PREPARED FROM THE LEAF EXTRACT OF Eucalyptus camaldulensis

Herein we report the green synthesis of silver nanoparticles (EcAgNPs) from water fraction (Ecs), obtained from methanol extract of Eucalyptus camaldulensis at room conditions. UV-vis, HR-TEM and SEM-EDS devices were used to characterize the EcAgNPs. The UV-visible spectrum of EcAgNPs showed surface plasmon resonance peak at 420 nm. HR-TEM images showed that the EcAgNPs were spherical with a diameter in the range 3.7-29.6 nm. Ag+ ions were reduced to Ago by phytochemicals in the without adding external reducing agent. The presence of biomolecules in the Ecs was investigated by UPLC-MS/MS that detected gallic acid (20.26±0.10 ppb) and quercetin (12.4±0.08 ppb) as major constituents. The antimicrobial activities of Ecs and synthesized EcAgNPs were tested on Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis, Staphylococcus aureus strains and Candida albicans yeast. Ecs exhibited antimicrobial activity as MIC between 16.2 and 129.3 mg mL-1 while EcAgNP showed MIC between 6.31 and 14.65 µgmL-1. The cytotoxicity of both Ecs and EcAgNPs on A549, HT29 and MDA-MB-231 cancer cell lines was tested by MTT. EcAgNPs showed more significant anticancer activity on MDA-MB-231, HT29 and A549 cancer cell lines (8.10±0.01, 5.08±0.01 and 18.58±0.03 µg mL-1) than Ecs (219.70±0.73, 916.24±0.67, 999.30±1.86 µg mL-1) and it should be investigated for use in various therapeutics.