Eco-friendly Synthesis Of Silver Nanoparticles Research Articles

Photobiologic-mediated fabrication of silver nanoparticles with antibacterial activity

We present the simple, eco-friendly synthesis of silver nanoparticles (AgNPs) using sunlight or green, red, blue, or white LED light together with Dryopteris crassirhizoma rhizome extract (DCRE) as the reducing and capping agent. The preliminary indication of AgNP production was a color change from yellowish green to brown after light exposure in the presence of DCRE. Optimization of parameters such as pH, inoculum dose, and metal ion concentration played an important role in achieving nanoparticle production in 30min. The spectroscopic and morphological properties of AgNPs were characterized using UV–Vis spectroscopy through the presence of a characteristic surface plasmon resonance (SPR) band for AgNPs, Fourier transform infrared spectroscopy (FT-IR), high-resolution transmission electron microscopy (HR-TEM), and X-ray diffraction (XRD). The FT-IR results indicated that the phytochemical present in DCRE was the probable reducing/capping agent involved in the synthesis of AgNPs, and light radiation enhanced nanoparticle production. HR-TEM revealed that the AgNPs were almost spherical with an average size of 5–60nm under all light sources. XRD studies confirmed the face cubic center (fcc) unit cell structure of AgNPs. The synthesized AgNPs showed good antimicrobial activity against Bacillus cereus and Pseudomonas aeruginosa. This study will bring a new insight in ecofriendly production of metal nanoparticles.

Green synthesis and catalytic application of silver nanoparticles using Carissa carandas fruits

ABSTRACTThe present work describes the eco-friendly synthesis of silver nanoparticles using dried fruit extract of C. carandas. The synthesized AgNPs were characterized by UV-Vis analysis, FTIR, XRD, SEM, and TEM with histogram. The TEM image of the precipitated solid phase of AgNPs showed in the range of 23 ± 2 nm in size. Further, the catalytic degradation on crystal violet dye in the presence of C. carandas dried fruit extract and AgNPs was also studied.

Caulerpa racemosa: a marine green alga for eco-friendly synthesis of silver nanoparticles and its catalytic degradation of methylene blue.

In this study, a simple and green method has been demonstrated for the synthesis of highly stable silver nanoparticles (AgNPs) using aqueous extract of Caulerpa racemosa (C. racemosa) as a reducing and capping agent. The formation and stability of AgNPs were studied using visual observation and UV-Visible (UV-Vis) spectroscopy. The stable AgNPs were further characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy and high resolution transmission electron microscopy (HR-TEM) with energy dispersive spectroscopic (EDS) methods. The biosynthesized AgNPs showed a sharp surface plasmon resonance peak at 441nm in the visible region and they have extended stability which has been confirmed by the UV-Vis spectroscopic results. XRD result revealed the crystalline nature of synthesized AgNPs and they are mainly oriented in (111) plane. FT-IR studies proved that the phytoconstituents of C. racemosa protect the AgNPs from aggregation and also which are responsible for the high stability. The size of synthesized AgNPs was approximately 25nm with distorted spherical shape, identified from the HR-TEM images. The synthesized AgNPs showed excellent catalytic activity towards degradation of methylene blue.

Low-cost and eco-friendly synthesis of silver nanoparticles using coconut (Cocos nucifera) oil cake extract and its antibacterial activity

The present study reports the simple, inexpensive, eco-friendly synthesis of silver nanoparticles (AgNPs) using coconut oil cake extract. Scanning electron microscopy–energy dispersive spectroscopy peak at 3 keV confirmed the presence of silver. Transmission electron micrograph showed that nanoparticles are mostly circular with an average size of 10–70 nm. The results of the X-ray powder diffraction analysis (2θ = 46.2, 67.4 and 76.8) indicated the crystal nature of the AgNPs. Fourier transform infrared spectroscopy analysis indicates that proteins present in the oilcake extract could be responsible for the reduction of silver ions. The synthesized AgNPs (1–4 mm) reduced the growth rate of multi-antibiotic-resistant bacteria such as Aeromonas sp., Acinetobacter sp. and Citrobacter sp. isolated from livestock wastewater.

Ultrasound assisted green synthesis of silver nanoparticles using weed plant.

This study presents the facile, green and eco-friendly synthesis of silver nanoparticles (AgNPs) using weed plant Lantana camara L. leaf extract. The incorporation of ultrasound into this reduced the time and increased the reaction rate. The results showed that the AgNPs were spherical in shape with the average size of 33.8 nm. The EDAX pattern indicated the presence of abundant silver and XRD indicated that the (111) crystallographic plane more predominant than other planes. The possible functional groups responsible for the reduction and stabilization of AgNPs were identified using Fourier transform infrared spectroscope. The XPS results concluded that the nanoparticles were presented in its reduced metallic state. The antioxidant activity of AgNPs was assayed using 2, 2-diphenyl-1-picrylhydrazyl (DPPH) test. The increase in the concentration of AgNPs increased the DPPH scavenging activity. The AgNPs revealed superior antibacterial activity against Gram positive and Gram negative organisms.

Green and ecofriendly synthesis of silver nanoparticles: Characterization, biocompatibility studies and gel formulation for treatment of infections in burns

The current study summarizes a unique green process for the synthesis of silver nanoparticles (AgNPs) by simple treatment of silver nitrate with aqueous extract of Ammania baccifera. Phytosynthesized AgNPs were characterized by various advanced analytical methods and studied for its use against infections associated with burns. Formation of AgNPs was observed by visual color change from colorless to dark brown and confirmed by UV–visible characteristic peak at 436nm. Zeta potential, particle size and polydispersity index of nano-silver were found to be −33.1±1.12, 112.6±6.8nm and 0.3±0.06 respectively. XRD spectra revealed crystalline nature of AgNPs whereas TEM confirmed the presence of mixed morphology of AgNPs. The overall approach designated in the present research investigation for the synthesis of AgNPs is based on all 12 principles of green chemistry, in which no man-made chemical other than the silver nitrate was used. Synthesized nano-silver colloidal dispersion was initially tested for minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) against a panel of organisms involved in infections associated with burns (Pseudomonas aeruginosa (PA), Staphylococcus aureus (SA) and methicillin resistant S. aureus (MRSA)). MIC and MBC were found to be in range of 0.992 to 7.93 and 7.93 to 31.75μg/mL respectively. MBC was used for formulation of AgNP gel and tested for its efficacy using agar well diffusion method against PA, SA and MRSA. Comparative bactericidal efficacy of formulated gel (0.03% w/w) and marked formulation Silverex™ ionic (silver nitrate gel 0.2% w/w) showed equal zone of inhibition against all pathogenic bacteria. Formulated AgNP gel consisting of 95% lesser concentration of silver compared to marketed formulation was found to be equally effective against all organisms. Hence, the formulated AgNP gel could serve as a better alternative with least toxicity towards the treatment presently available for infections in burns.

Cobweb as novel biomaterial for the green and eco-friendly synthesis of silver nanoparticles

In this study, spider cobweb as a novel biomaterial was used for the green synthesis of silver nanoparticles (AgNPs). The synthesized AgNPs were characterized using UV–Vis spectroscopy, Fourier-transform infrared spectroscopy (FTIR), and transmission electron microscopy. The efficacy of biosynthesized particles as antibacterial agents was evaluated using multi-drug resistant clinical bacterial isolates through sensitivity testing with AgNPs and combination of AgNPs with some selected antibiotics. In addition, the potential application of the particles as additives in paints was demonstrated using some bacterial and fungal isolates. The synthesized AgNPs which were dark brown in color displayed maximum absorbance at the wavelength of 436 nm. It was observed that the reaction mixture of 1:40 (extract:AgNO3 solution) at pH of 8.5 produced particles with maximum absorbance at 436 nm. The FTIR spectrum showed peaks at 3298, 2359, 2089, and 1635 cm−1, indicating that proteins were the capping and stabilization molecules in the synthesis of AgNPs. The particles were spherical in shape with size ranging about 3–50 nm. The energy-dispersive X-ray analysis showed the presence of silver as the most prominent metal, while the selected area electron diffraction pattern conformed to the face-centered cubic phase and crystalline nature of AgNPs. The AgNPs inhibited the growth of several bacterial isolates including S. aureus, E. coli, Klebsiella granulomatis and P. aeruginosa in the range of 10–17 mm at concentration of 100 µg/ml. It was also demonstrated that AgNPs potentiated the activities of augmentin, ofloxacin and cefixime in the AgNP–antibiotic synergy studies. Similarly, the inclusion of AgNPs as additive in white emulsion paint led to the total inhibition of growth of E. coli, P. aeruginosa, Aspergillus niger and A. fumigatus. To the best of our knowledge, this is the first report of the use of cobweb for the green synthesis of AgNPs. The immense antimicrobial activities of the particles can be explored in the creation of novel products, where it can be used as additive to protect materials against microbial attack.

Green synthesis of silver nanoparticles using leaf extract of medicinally potent plant Saraca indica: a novel study

Eco-friendly silver nanoparticles (AgNPs) have various applications in modern biotechnology for better outcomes and benefits to the society. In the present study, we report an eco-friendly synthesis of silver nanoparticles using Saraca indica leaf extract. Characterization of S. indica silver nanoparticles (SAgNPs) was carried out by Fourier transform infrared spectroscopy, scanning electron microscopy, energy dispersive spectrometry, Zeta potential, and transmission electron microscopy. SAgNPs showed antimicrobial activity against Gram-negative and Gram-positive bacteria.

Characterization and antibacterial activity of plant mediated silver nanoparticles biosynthesized using Scrophularia striata flower extract

In the study, an eco-friendly synthesis of silver nanoparticles (AgNPs) has been reported using aqueous extract of Scrophularia striata flower. The extract acts as reducing as well as stabilizing agent. To obtain the optimized conditions for synthesis of AgNPs, the effect of process variables such as extract concentration, concentration ratio of the reactants and time were studied using UV-Vis spectroscopy. The UV-Vis results showed a peak at 440 nm corresponding to the surface plasmon resonance in the optimized conditions (10% extract concentration, 1 : 1.5 concentration ratio of the reactants and time of 24 h). The synthesized AgNPs were also characterized using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and Fourier transform infrared spectroscopy (FTIR). According to the XRD patterns, the size of the AgNPs was calculated in the range of 8—12nm. The FESEM images showed the spherical shape of AgNPs. The FTIR spectrum showed the presence of various functional groups such as hydroxyl, amine and carbonyl groups. Finally, the antibacterial activity of the synthesized AgNPs was evaluated against Staphylococcus aureus (Gram positive) and Escherichia coli (Gram negative). The results showed that the colloidal solution of AgNPs has antibacterial activity against both different strains of bacteria.

Eco-friendly synthesis of silver nanoparticles using leaf extract of Grewia flaviscences and study of their antimicrobial activity

In this work, we report the eco-friendly synthesis of silver nanoparticles (AgNPs) by bio-reduction method. Aqueous extract of Grewia flaviscences plant leaf was used as stabilizing and reducing agent. Formation of AgNPs was initially identified by change in color from light yellow to dark brown. UV–visible spectra showed the characteristic surface Plasmon resonance peak of synthesized AgNPs between 380 and 460nm. X-ray diffraction analysis revealed the crystalline nature of AgNPs, whereas Energy-dispersive X-ray spectroscopy confirms the metallic nature of silver. Field emission scanning electron microscopy and transmission electron microscopy images showed the spherical nature of the particles whereas size distribution was measured by Zetasizer, which revealed that size of AgNPs were in the range of 50–70nm. Biosynthesized AgNPs exhibited antimicrobial activity against both gram positive and gram negative bacteria, Bacillus and Pseudomonas aeruginosa. Sps., respectively. The effects of leaf extract and silver nitrate concentrations on AgNPs have also been studied.

Sunlight-induced rapid and efficient biogenic synthesis of silver nanoparticles using aqueous leaf extract of Ocimum sanctum Linn. with enhanced antibacterial activity.

BackgroundNanotechnology is now regarded as a distinct field of research in modern science and technology with multifaceted areas including biomedical applications. Among the various approaches currently available for the generation of metallic nanoparticles, biogenic synthesis is of increasing demand for the purpose of green nanotechnology. Among various natural sources, plant materials are the most readily available template-directing matrix offering cost-effectiveness, eco-friendliness, and easy handling. Moreover, the inherent pharmacological potentials of these medicinal plant extracts offer added biomedical implementations of the synthesized metal nanoparticles.ResultsA robust practical method for eco-friendly synthesis of silver nanoparticles using aqueous leaf extract of Ocimum sanctum (Tulsi) as both reducing and capping agent, under the influence of direct sunlight has been developed without applying any other chemical additives. The nanoparticles were characterized with the help of UV-visible spectrophotometer and transmission electron microscopy (TEM). The prepared silver nanoparticles exhibited considerable antibacterial activity. The effects were more pronounced on non-endospore-forming Gram-positive bacteria viz., Staphylococcus aureus, Staphylococcus epidermidis, and Listeria monocytogenes than endospore-forming species Bacillus subtilis. The nanoparticles also showed prominent activity on Gram-negative human pathogenic Salmonella typhimurium, Escherichia coli, Pseudomonas aeruginosa, and plant pathogenic Pantoea ananatis. A bactericidal mode of action was observed for both Gram-positive and Gram-negative bacteria by the nanoparticles.ConclusionsWe have developed a very simple, efficient, and practical method for the synthesis of silver nanoparticles using aqueous leaf extract of O. sanctum under the influence of direct sunlight. The biosynthesis of silver nanoparticles making use of such a traditionally important medicinal plant without applying any other chemical additives, thus offers a cost-effective and environmentally benign route for their large-scale commercial production. The nanoparticles dispersed in the mother solution showed promising antibacterial efficacy.Graphical Sunlight-induced rapid and efficient biogenic synthesis of silver nanoparticles using aqueous leaf extract of Ocimum sanctum Linn. with enhanced antibacterial activity.Electronic supplementary materialThe online version of this article (doi:10.1186/s13588-014-0018-6) contains supplementary material, which is available to authorized users.

Synthesis of eco-friendly silver nanoparticles from Morinda tinctoria leaf extract and its larvicidal activity against Culex quinquefasciatus.

Mosquitoes are the major vector for the transmission of malaria, dengue fever, yellow fever, filariasis, chikungunya and Japanese encephalitis, and they accounted for global mortality and morbidity with increased resistance to common insecticides. The aim of this study was to investigate the larvicidal potential of the acetone leaf extracts of Morinda tinctoria and synthesized silver nanoparticles against third instar larvae of Culex quinquefasciatus Say (Diptera: Culicidae). Nanoparticles are being used in many commercial applications. It was found that aqueous silver ions can be reduced by aqueous extract of plant parts to generate extremely stable silver nanoparticles in water. Synthesized AgNPs were characterized by ultraviolet-visible (UV-vis) spectroscopy, Atomic force microscopy (AFM) and Fourier transform infrared spectroscopy (FT-IR) analysis. The synthesized silver nanoparticles have also been tested against the third instar larvae of C. quinquefasciatus. The leaf extract and the AgNPs high mortality values were 50 % lethal concentration (LC50) = 8.088 and 1.442 ppm against C. quinquefasciatus, respectively. The results recorded from ultraviolet-visible spectroscopy, atomic force microscopy and Fourier transform infrared spectroscopy support the biosynthesis and characterization of silver nanoparticles. These results suggest that the leaf extract of M. tinctoria and synthesis of AgNPs have the potential to be used as an ideal eco-friendly approach for the control of C. quinquefasciatus. By this approach, it is suggestive that this rapid synthesis of nanoparticles would be proper for developing a biological process for mosquito control.

Marine Streptomyces cyaneus Strain Alex-SK121 Mediated Eco-friendly Synthesis of Silver Nanoparticles Using Gamma Radiation

Aim: The present study aimed to develop cost-effective, eco-friendly marine Streptomyces cyaneus strain Alex-SK121 mediated synthesis of silver nanoparticles (AgNPs) with antimicrobial, antitumor and antioxidant activities.Methodology: Aqueous 1mM silver nitrate (AgNO3) solution was treated with cell-free supernatant (CFS) of a novel Streptomyces cyaneus strain Alex-SK121 isolated from marine sediment samples. The prepared solution was irradiated with different doses of gamma rays ranged from 0.5 to 30.0kGy. Initial characterization of the synthesized AgNPs was performed by visual observation of color change in the prepared solution followed by analysis of UV-Visible Spectrophotometer (UV-Vis.), Fourier Transform Infrared Spectrometer (FT-IR), Dynamic Light Scattering (DLS) and Transmission Electron Microscopy (TEM). Evaluation of antimicrobial activity of the synthesized AgNPs against some pathogenic microorganisms was carried out. Antitumor activity of AgNPs was carried out against some human cancer cell lines using the method of Sulphorodamine B (SRB) assay, antioxidant activity of AgNPs was also studied using DPPH scavenging assay.Results: In the present study, the cell-free supernatant of Streptomyces cyaneus strain Alex-SK121 isolated from sediment samples collected from Sidi Kerir region, Alexandria governorate, Egypt was found to reduce Ag+ ions to AgNPs. Identification of the producer strain was performed according to spore morphology and cell wall chemo-type, which suggested that this strain is Streptomyces. Further cultural, physiological characteristics and analysis of the nucleotide sequence of 16S rRNA gene indicated that this strain is identical to Streptomyces cyaneus and then designated Streptomyces cyaneus strain Alex-SK121. To maximize the production of AgNPs, the tested supernatant was irradiated with different doses of gamma rays and it was found that, 15 kGy is the best applied dose induces AgNPs synthesis. The synthesized AgNPs showed the characteristic absorption spectra in UV–Vis. at 425 nm. The microbiologically synthesized AgNPs showed significant antimicrobial activity towards some pathogenic microorganisms with inhibition zone ranged from 13 up to 20 mm. Also AgNPs exhibited antitumor activity against human breast carcinoma cells and human liver carcinoma cells with IC50 9.63 and 33.75 µg/ml respectively in addition to 96% antioxidant activity.Conclusion: Gamma irradiation which induced AgNPs synthesis by cell-free supernatant of marine actinomycetes Streptomyces cyaneus strain Alex-SK121 with different applications is a simple, clean, economic and environmental friendly approach.

Electrocatalytic Reduction of Benzyl Chloride by Green Synthesized Silver Nanoparticles Using Pod Extract of Acacia nilotica

The present work describes the eco-friendly synthesis of silver nanoparticles using pod extract of Acacia nilotica. The effect of concentration and effect of pH were studied on the synthesis of sil...

Synthesis of silver nanoparticles using cow milk and their antifungal activity against phytopathogens

Silver nanoparticles have wide application in different scientific fields. The present study reports the simple and eco-friendly synthesis of silver nanoparticles using cow milk. The X-ray diffraction peaks (2θ—37.76, 46.12, 67.4, and 76.84) and scanning electron microscopy–energy dispersive spectroscopy peak, approximately at 3keV, confirmed the presence of silver nanoparticles. Transmission electron micrograph showed that nanoparticles are mostly circular with an average size of 30–90nm. The proteins present in cow milk could be responsible for Ag+ ions reduction. The synthesized nanoparticles (2mM) can significantly inhibit (87.1%, 86.5%, and 83.5%) the growth of phytopathogens Colletotrichum coccodes, Monilinia sp., and Pyricularia sp.

Totally Ecofriendly Synthesis of Silver Nanoparticles from Aqueous Dissolutions of Polysaccharides

In this contribution, a totally ecofriendly synthesis of silver nanoparticles from aqueous dissolution of polysaccharides is reported. The synthesis of nanoparticles was performed using aqueous dissolutions of silver nitrate (AgNO3) and carboxymethyl-cellulose (CMC) as both reducing and stabilization agent and using different AgNO3 : CMC weight ratios. Resultant yellowish to reddish dispersions were characterized by means of transmission electron microscopy and their related techniques, such as bright field and Z-contrast imaging and electron diffraction, as well as ultraviolet-visible and infrared spectroscopic techniques. The experimental evidence suggests that the morphology and particle size distribution of the silver nanoparticles depend on the AgNO3 : CMC weight ratio. This feature seems to be related to the stabilization given by the CMC matrix, which, according to our experimental findings, is steric in nature. Regarding such experimental evidence, a synthesis mechanism in which CMC acts as stabilizer and reducing agent is proposed.

Eco-Friendly Synthesis of Silver Nanoparticles Using Carica Papaya Extract for Anti Bacterial Applications

Nanobiotechnology emerged as integration of nanotechnology and biotechnology for developing bioactive, biosynthetic and eco -friendly technology for synthesis of nanomaterials. Nanostructures have great demand in areas such as chemistry, catalysis, electronics, energy, and medical applications. Metallic nano-particles are normally synthesized by wet chemical synthesis techniques using the toxic and inflammable chemicals. Present research work on preparation of silver nano-particles by green nano synthesis method and has advantages over conventional methods involving chemical agents which can cause environmental toxicity. The synthesis technique is a cost effective and environment friendly technique for green nano synthesis of silver nano-particles from varying concentrations of AgNO3 solution and extract of Carica papaya fruit of different concentrations which acts as reducing and capping agent. Characterizations has been done using UV–Vis absorption spectroscopy, XRD, particle size analyser and SEM with EDX. Antimicrobial activity was done using Escherichia coli and Pseudomonas.