Green synthesis of silver nanoparticles using aqueous solution of Ficus benghalensis leaf extract and characterization of their antibacterial activity

The present study reports an environmentally friendly and rapid method for synthesis of silver nanoparticles. Although several articles have been reported for the synthesis of silver nanoparticles from plant extract, here we have developed a green synthetic method for silver nanoparticles using Ficus benghalensis leaf extract which acts as a reducing and capping agent. It was observed that use of Ficus benghalensis leaf extract makes a fast and convenient method for the synthesis of silver nanoparticles and can reduce silver ions into silver nanoparticles within 5 min of reaction time without using any harsh conditions. Silver nanoparticles so prepared were characterized by using UV-visible spectroscopy, transmission electron microscope-energy dispersive spectra (TEM-EDS) and X-ray diffraction (XRD). Further, these nanoparticles show effective antibacterial activity toward E.coli MTCC1302 due to high surface to volume ratio.     

Green synthesis of silver nanoparticles using marine polysaccharide: Study of in-vitro antibacterial activity

The present contribution deals with one pot method for synthesis of silver nanoparticles through green route using sulfated polysaccharide isolated from marine red algae (Porphyra vietnamensis). The obtained silver nanoparticles showed surface plasmon resonance centered at 404 nm with average particle size measured to be 13 ± 3 nm. FTIR spectra revealed the involvement of sulfate moiety of polysaccharide for reduction of silver nitrate. The capping of anionic polysaccharide on the surface of nanoparticles was confirmed by zeta potential measurement (−35.05 mV) and is responsible for the electrostatic stability. The silver nanoparticles were highly stable at wide range of pH (2-10) and electrolyte concentration (up to 10⁻² M of NaCl). The dose dependent effect of synthesized silver nanoparticles revealed strong antibacterial activity against gram negative bacteria as compared to gram positive bacteria.     

Facile photoreductive synthesis of silver nanoparticles for antimicrobial studies

In the present work, silver nanoparticles stabilized with L-Cysteine (L-Cys) were synthesized based on the one-pot green process by UV irradiation, in which L-Cysteine acts as biological capping agent. The composition and morphological characteristics of the L-Cys capped AgNPs has been ascertained by different techniques such as UV–vis, FL, XRD, TEM, EDX, FTIR and CD analysis. The results demonstrated the formation of spherical nanoparticles of pure Ag° coated with L-Cys. The antibacterial tests on L-Cys capped AgNPs were performed, exerting effective antimicrobial activity both against E. coli and S. aureus, with a minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of 21.9 μg/mL and 175 μg/mL, respectively. Considering this simple and green process, the approach may facilitate new approaches to the manufacture of AgNPs-based antibacterial agent.     

Green synthesis of silver oxide nanoparticles using Panicum miliaceum grains extract for biological applications

In this report, the silver oxide nanoparticles were green synthesized using Panicum miliaceum grains extract and were proposed for the first time. GC–MS analysis explicated 2-Acetylbenzoic acid was the active phytocompound with 97.07% of presence in aqueous grains extract. The synthesized silver oxide nanoparticles were analyzed by several analytical techniques such as UV–visible, XRD, FT-IR, HR-TEM, TG, XPS, EDX and mapping analyses. The results of various analytical techniques confirmed the silver oxide nanoparticles formation. The formed nanoparticles were in 10–25 nm size. The effectual bioactive properties of nanoparticles were revealed through antioxidant, anti-diabetic, anti-inflammatory, larvicidal and insecticidal activities. The high mortality of larvae and insect was observed at 48 h in 100 ppm and 72 h in 100 μg/Kg concentration, respectively. The antibacterial activity explained the bactericidal property of nanoparticles on S. aureus and S. typhi at 150 μg/mL concentration. The effective drug activity of nanoparticles was observed from 98.10 % of toxicity against A549 lung cancer cells at 100 μg/mL concentration. The growth of Vigna unguiculata was efficiently increased by lower concentration (60 ppm) of nanoparticles. According to results, the green synthesized nanoparticles can be applied in pharmaceutical and agricultural sectors as biocompatible, non-toxic and cost-effective material.     

Eco-friendly green synthesis of silver nanoparticles and their potential applications as antioxidant and anticancer agents

Abstract

Eco-friendly green synthesis of nanoparticles using medicinal plants gained immense importance due to its potential therapeutic uses. In the current study, silver nanoparticles (AgNPs) were synthesized using water extract of Jurinea dolomiaea leaf and root at room temperature. MTT assay was used to study anticancer potential of AgNPs against cervical cancer cell line (HeLa), breast cancer cell lines (MCF-7), and mouse embryonic fibroblast (NIH-3 T3) cell line for toxicity evaluation. The antioxidant potential was evaluated using stable DPPH radicals. In addition, the apoptotic nuclear changes prompted by AgNPs in more susceptible HeLa cells were observed using fluorescence microscope through DAPI and PI staining. Physiochemical properties of biosynthesized AgNPs were characterized using various techniques. AgNPs were formed in very short time and UV–vis spectra showed characteristic absorption peak of AgNPs. SEM and TEM showed spherical shape of AgNPs and XRD revealed their crystalline nature. EDX analysis revealed high percentage of silver in green synthesized AgNPs. FTIR analysis indicated involvement of secondary metabolites in fabrication of AgNPs. In vitro cytotoxic and antioxidant study revealed that herb and biosynthesized AgNPs exhibited significant dose-dependent and time-dependent anticancer and antioxidant potential. Furthermore, study on normal cell line and microscopic analysis of apoptosis revealed that AgNPs exhibited good safety profile as compared to cisplatin and induces significant apoptosis effect. Based on the current findings, it is strongly believe that use of J. dolomiaea offers large scale production of biocompatible AgNPs that can be used as alternative anticancer agents against cancer cell lines tested.     

Synthesis,characterization and antibacterial activity of superparamagnetic nanoparticles modified with glycol chitosan

Iron oxide nanoparticles (IONPs) were synthesized by coprecipitation of iron salts in alkali media followed by coating with glycol chitosan (GC-coated IONPs). Both bare and GC-coated IONPs were subsequently characterized and evaluated for their antibacterial activity. Comparison of Fourier transform infrared spectra and thermogravimetric data of bare and GC-coated IONPs confirmed the presence of GC coating on IONPs. Magnetization curves showed that both bare and GC-coated IONPs are superparamagnetic and have saturation magnetizations of 70.3 and 59.8 emu g⁻¹, respectively. The IONP size was measured as ∼8–9 nm by transmission electron microscopy, and their crystal structure was assigned to magnetite from x-ray diffraction patterns. Both bare and GC-coated IONPs inhibited the growths of Escherichia coli ATCC 8739 and Salmonella enteritidis SE 01 bacteria better than the antibiotics linezolid and cefaclor, as evaluated by the agar dilution assay. GC-coated IONPs showed higher potency against E. coli O157:H7 and Staphylococcus aureus ATCC 10832 than bare IONPs. Given their biocompatibility and antibacterial properties, GC-coated IONPs are a potential nanomaterial for in vivo applications.     

Synthesis,characterization and antibacterial activity of superparamagnetic nanoparticles modified with glycol chitosan

Abstract

Iron oxide nanoparticles (IONPs) were synthesized by coprecipitation of iron salts in alkali media followed by coating with glycol chitosan (GC-coated IONPs). Both bare and GC-coated IONPs were subsequently characterized and evaluated for their antibacterial activity. Comparison of Fourier transform infrared spectra and thermogravimetric data of bare and GC-coated IONPs confirmed the presence of GC coating on IONPs. Magnetization curves showed that both bare and GC-coated IONPs are superparamagnetic and have saturation magnetizations of 70.3 and 59.8 emu g^?1, respectively. The IONP size was measured as ～8–9 nm by transmission electron microscopy, and their crystal structure was assigned to magnetite from x-ray diffraction patterns. Both bare and GC-coated IONPs inhibited the growths of Escherichia coli ATCC 8739 and Salmonella enteritidis SE 01 bacteria better than the antibiotics linezolid and cefaclor, as evaluated by the agar dilution assay. GC-coated IONPs showed higher potency against E. coli O157:H7 and Staphylococcus aureus ATCC 10832 than bare IONPs. Given their biocompatibility and antibacterial properties, GC-coated IONPs are a potential nanomaterial for in vivo applications.     

壳聚糖修饰银纳米颗粒的制备及抗菌性能研究

采用液相化学还原法,以壳聚糖为修饰剂,硼氢化钠为还原剂,制备了壳聚糖修饰银纳米颗粒(chitosan-Ag NPs)。通过X射线粉末衍射仪、透射电子显微镜、傅立叶变换红外光谱仪等对所制备样品的结构和形貌进行了表征。结果表明,所制备纳米颗粒具有面心立方Ag的晶型结构,壳聚糖通过氨基和羟基中的N、O原子与Ag+的化学键合作用修饰在纳米颗粒表面,起到了限制颗粒粒径长大和防止其团聚的作用。采用肉汤连续稀释法检测了样品对大肠杆菌和金黄色葡萄球菌的抑菌杀菌性能,结果表明chitosan-Ag NPs具有优异的抗菌性,抗菌性能受到粒径大小的影响。     

A facile method to prepare size-tunable silver nanoparticles and its antibacterial mechanism

The antibacterial effect of silver nanoparticles (denoted as Ag NPs) is closely related to size. This could partly explain why size controllable synthesis of Ag NPs for bactericidal application is drawing much attention. Thus, we establish a facile and mild route to prepare size-tunable Ag NPs with highly uniform morphologies and narrow size distributions. The as-prepared Ag NPs with averaged sizes of 2, 12 and 32?nm were characterized by transmission electron microscopy (TEM), ultraviolet–visible absorption spectroscopy (UV–vis), X-ray powder diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The antimicrobial effect of the as-prepared Ag NPs with different particles size was assessed by broth dilution and disk diffusion as well as measurement of optical density (OD₆₀₀). Moreover, their antibacterial mechanism was discussed in relation to morphology observation of microorganism by scanning electron microscopy (SEM) and to concentration detection of Ag⁺ by stripping voltammetry. It was found that the parameters such as reactant molar ratio, reaction time, dropping speed, and most of all, pH of the reactant solutions, have significant influences on size-regulation of Ag NPs. The as-prepared Ag NPs exhibit excellent antibacterial properties, and their antimicrobial activities increase with decreasing particles size. Besides, two kinds of mechanisms, i.e., contact action and release of Ag⁺, are responsible for the antimicrobial effect of Ag NPs.     

Nigella arvensis leaf extract mediated green synthesis of silver nanoparticles: Their characteristic properties and biological efficacy

In the present study, the potential of aqueous leaf extract of Nigella arevensis for biosynthesis of silver nanoparticles (AgNPs) was evaluated. The formation of AgNPs was confirmed by color changes and UV–visible spectroscopy, which showed absorbance maxima peak at 416?nm. The transmission electron microscope (TEM) image showed the AgNPs to be anisotropic and mostly spherical with sizes in the range of 5–100?nm. Fourier transform infrared (FTIR) analysis indicated that the flavonoids, alkaloids and phenolic groups present in leaf extract were involved in the reduction and capping of phytogenic AgNPs. These nanoparticles showed the cytotoxic effects against H1229 and MCF-7 cancer cell lines with an IC₅₀ value of 10?μg/mL. AgNPs showed insignificant antioxidant properties compared to the crude extract, and it was effective against clinical isolated bacterial strains. Furthermore, the bioderived AgNPs displayed significant catalytic activity against methylene blue. These results confirmed the advantages and applications of these phytogenic AgNPs using the green method in various fields.     

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.     

Comparison of antibacterial activity of Ag nanoparticles synthesized from leaf extract of Parthenium hystrophorus L in aqueous media and Gentamicin sulphate: in-vitro

Monodisperse silver (Ag) nanoparticles were synthesized by using Parthenium hystrophorus L leaf extract in aqueous media. The synthesized nanoparticles were characterized by using UV-vis spectrophotometer, X-ray diffracto-meter (XRD), transmission electron microscope (TEM), and dynamics light scattering (DLS). Size-dependent antibacterial activities of Ag nanoparticles were tested against Gram negative Pseudomonas aeruginosa and Gram positive Staphylococcus aureus. Ag nanoparticles having 20?±?2?nm size in diameter show maximum zone of inhibition (23?±?2.2?mm) in comparison to 40?nm and 70?nm diameter nanoparticles for Pseudomonas aeruginosa. The zone of inhibition against Staphylococcus aureus were 19?±?1.8?mm, 15?±?1.5?mm and 11?±?1?mm for 20?nm, 40?nm, and 70?nm, respectively. In addition, affect of concentration of 20?nm size Ag nanoparticles on Bacillus cereus, Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus species were also reported and results were compared with 10?µg/ml dose of Gentamicin sulphate. The Parthenium hystrophorus L leaf extract capped 20?±?2?nm Ag nanoparticles (7.5?µg/ml) shows statistically significant antibacterial activity than Gentamicin sulphate (10?µg/ml) against Staphylococcus aureus.     

Fabrication of antibacterial monodispersed Ag-SiO2 core-shell nanoparticles with high concentration

Monodispersed Ag-SiO₂ core-shell nanoparticles with a high concentration of 400 mg/L were successfully fabricated by using tetraethoxysilane as silica precursor and reducing silver nitrate with ascorbic acid in the presence of cetyltrimethylammonium bromide as stabilizing agent. The nanoparticles had a spherical silver core in a size range from 14-26 nm in diameter and an amorphous silica shell of 15-28 nm thickness, respectively. The antibacterial effects of Ag-SiO₂ core-shell particles against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) were tested by the usual twofold serial dilution method for minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC). The results indicated that the core-shell nanoparticles owned excellent antibacterial effects.     

Green synthesis of colloidal silver nanoparticles by sonochemical method

A facile sonochemical method was developed for preparing colloidal silver nanoparticles (Ag-NPs) in aqueous gelatin solutions. The effect of the reducing agent and Ag⁺ concentrations, ultrasonic time, and ultrasonic amplitude on the particle size has been investigated. The size of the Ag-NPs decreases with the ultrasonic amplitude and increases with ultrasonic time. Well-dispersed spherical Ag-NPs with a mean particle size of about 3.5 nm have been synthesized under ultrasonic process. The use of gelatin as an eco-friendly stabilizer provides green and economic attributes to this work. This preparation method is general and may be extended to other noble metals, such as Au, Pd and Pt, and may possibly find various additional medicinal, industrial and technological applications.     

Green synthesis and characterisation of antioxidant-tagged gold nanoparticle (X-GNP) and studies on its potent antimicrobial activity

Alternanthera philoxeroides (Mart.), a weed, mainly from tropical origin and easily available worldwide. People used to eat it as a food mainly in South Africa. In our previous report we have thoroughly characterise several important phenolics, monoterpene and phenylpropane from methanol soluble fraction of Alternenthera leaves (fraction X) and also reported their α-glucosidase inhibitory, antimicrobial and antioxidant activities. All these isolated natural compounds are well characterised and widely studied. In our present study we try to use this beneficial fraction (named fraction X) in green synthesis of gold nanoparticles (X-GNP). We also try to explore the beneficial aspects of green synthesis in comparison with commonly used chemical synthesis method (GNP) in context with their antimicrobial activity. UV/Vis spectroscopy, DLS, Zeta potential, FT-IR, EDAX and other microscopic techniques namely: SEM, AFM were used to characterise the synthesised nanoparticles. Different important microbial strains were used to evaluate the antimicrobial activity of prepared nanoparticles. Overall the studies suggest successful synthesis of green nanoparticles (X-GNP) and also showed the improvement in antimicrobial activity of X-GNP nanoparticles.     

Rapid biologically one-step synthesis of stable bioactive silver nanoparticles using Osage orange (Maclura pomifera) leaf extract and their antimicrobial activities

Synthesis of nanoparticles by using natural products as reducing and stabilizing agents have been widely used in various fields especially medicine, primarily because of its lower cost, simplicity, and less toxic byproducts. In the present work, silver nanoparticles (Ag NPs) were rapidly synthesized from silver nitrate in a green one-step synthesis by the aqueous extracts of Osage orange (Maclura pomifera) leaf as a reducing and stabilizing agent simultaneously. The effects of pH, extract quantity, and silver salt concentration were investigated to determine the optimum conditions of green synthesis of Ag NPs. The synthesized Ag NPs were characterized by different techniques including UV–Visible (UV–Vis) absorption spectroscopy, X-ray diffraction (XRD), Fourier transform Infrared (FT-IR) Spectroscopy, and Transmission Electron Microscopy (TEM). The Ag NPs showed surface plasmon resonance centered at 415?nm. The XRD pattern and TEM analysis revealed spherical, stable, and uniform Ag NPs with the average particle size of about 12?nm. The FT-IR spectroscopy showed that mainly hydroxyl functional groups, as both the reducing and stabilizing agent are responsible for silver nanoparticles synthesis. The antimicrobial activity of the synthesized Ag NPs showed a significant microbicidal effect on all clinical isolates especially, Gram-negative bacteria and fungi. These results suggest that such stable and uniform Ag NPs can be synthesized rapidly and simply for clinical as well as pharmaceutical applications.     

Green synthesis of nickel oxide nanoparticles and studies of their photocatalytic activity in degradation of polyethylene films

Nickel oxide nanoparticles (NiO NPs) were synthesized using Ananas comosus leaf extract, and were characterized by UV–Vis spectroscopy, Fourier transform infrared (FTIR) spectroscopy, high resolution transmission electron microscopy (HRTEM), Energy dispersive X-ray (EDX) and X-ray diffraction (XRD) techniques. The FTIR analysis confirms the formation of the NiO with appearance of NiO band at 468 cm⁻¹. The HRTEM analysis reveals that the NiO NPs size was in the range of 0.63–5.75 nm, with an average particle size of 1.42 ± 1.76 nm. The EDX analysis shows clear peaks of Ni (2.7%) and O (5.74%) in the spectrum. The peaks of XRD analysis at (2θ) 30°, 43.89°, 60.16°, 77.95° and 82.94° were assigned to (1 1 1), (2 0 0), (2 2 0), (3 1 1) and (2 2 2) planes of the face-centered cubic (fcc) lattice of NiO. The photocatalytic properties of the NiO NPs were studied through the solid phase degradation of low-density polyethylene (LDPE) film. We observed that polymeric nanocomposites (NCs) showed a significant weight loss of 33 ± 1.6% compared with the pure LDPE (8.6 ± 0.7%) after exposure to solar light irradiation for 240 h, while the nanocomposites under the dark condition gave a weight reduction of 1.90 ± 0.05 at the end of 240 h. The FTIR analysis also confirms the presence of carbonyl group, a degradation product of LDPE, with carbonyl index of 0.4. All these important factors showed that NiO is an effective photocatalyst. The study therefore suggests the incorporation of NiO NPs into the polymer matrix so as to enhance its photodegradation.     

Green synthesis of copper oxide nanoparticles and its effective applications in Biginelli reaction,BTB photodegradation and antibacterial activity

Metal/metal oxide nanoparticles have gained much attention in the field of organic catalysis and photocatalysis reactions for development of greener methodology. In the present work, copper oxide nanoparticles (CuO NPs) were synthesized by a greener route using Cordia sebestena (C. sebestena) flower aqueous extract. The nanoparticles were evaluated for their catalytic efficiency. The green synthesized CuO NPs were characterized using various analytical studies. A UV–Visible spectrum with peak at 267?nm and the peaks in their FT-IR spectrum at 431 and 542?cm^?1 showed reduction by the plant metabolites. FESEM-EDX analysis of CuO NPs shows an agglomerated spherical shape with signatures of Cu and O and XRD reveals characteristic crystallinity. TEM and DLS analyses showed particle size between 20 and 35?nm and TEM-SAED pattern ensured crystallinity. A Zeta potential of ?26?mV demonstrates moderate stability. The CuO NPs acted as a catalyst in the Biginelli reaction to produce 3,4-dihydropyrimidinones rapidly and at high yield. The NPs also degraded bromothymol blue (BTB) by photocatalysis with hydrogen peroxide. 100% dye removal efficiency was achieved by 3?h exposure of BTB to natural sunlight inferring it as economy, ecofriendly and effective catalyst. This finding illustrates that the NPs could be used in photolysis to remove water pollutants. Moreover, the biological significance of green synthesized CuO NPs was assessed by antibacterial activity against selected pathogenic bacterial organisms.     

Ag-羧甲基壳聚糖复合微粒的制备及其抑菌活性

壳聚糖经羧甲基化改性后得到水溶性较高的羧甲基壳聚糖（OCMC）,它具有优良的稳定性和抗菌性。对比OCMC在不同溶剂中的溶解度,发现OCMC在2wt%乙酸溶液中的溶解性最好。将OCMC与纳米Ag（AgNPs）复合得到Ag-OCMC复合微粒,采用UV-Vis、FTIR、XPS、TEM、SEM和TG-DTA对Ag-OCMC复合微粒的组成、微观结构和热性能进行表征。以大肠杆菌和金黄色葡萄球菌为模型菌种测试Ag-OCMC复合微粒对革兰氏菌的抗菌性能。结果表明:AgNPs为面心立方晶型,平均粒径为40~50 nm;AgNPs的引入提高了壳聚糖和OCMC的分解温度。Ag-OCMC复合微粒对革兰氏菌的抑菌活性明显高于单一壳聚糖基抗菌剂。      

Synthesis and antibacterial activity of stable bio-conjugated nanoparticles mediated by walnut (Juglans regia) green husk extract

Nanoparticles have gained significant attention in recent years due to their numerous applications in various aspects of human life. A variety of methods have been investigated for synthesis of nanoparticles among which, biogenic approaches are considered as both simple and eco-friendly. Here, a new single-step biological approach was employed for synthesis of silver chloride nanoparticles (AgCl-NPs) at room temperature, using walnut green husk extract. Macromolecules present in the plant extract, which might act as bio-reductants and/or stabilisers of nanoparticles were characterised by Fourier transform Infrared spectroscopy. X-ray diffraction pattern and transmission electron microscopy revealed that 1 mM of AgNO3 produced mostly spherical nanoparticles in a range of 4–30 nm in diameter with an average of 16 nm. Interestingly, the synthesised nanoparticles showed significant inhibitory effects against Escherichia coli and Staphylococcus aureus clinical isolates. Altogether, these data suggest a new encouraging application of a medicinal plant bound with synthesised AgCl nanoparticles.