Extracellular Synthesis Of Silver Nanoparticles Research Articles

Extracellular synthesis of silver nanoparticles using culture supernatant of Aspergillus Niger

A key aspect of nanotechnology concerns the development of reliable experimental protocolsfor the synthesis of nanomaterials over a range of chemical compositions, sizes, and highmonodispersity. The impetus of synthesis has shifted from physical and chemical processes towards‘green’ chemistry and bioprocesses .The use of microorganisms in the synthesis of nanoparticles is arelatively recent, new, and exciting area of research with considerable potential for development .Microorganisms like yeast, bacteria, and fungi play an important role in the remediation of toxic metalsby reducing them under stress conditions which forms the basis for the use of microorganisms in thebiosynthesis of nanoparticlesMaterial and methods:The biosynthesis of silver nanoparticles by A. niger isolated was carriedout in the present study. The fungal filtrate was treated with silver ions (AgNO3) in dark at 25 C, whichshowed a change in colour from yellow to dark-brown.The colour change of the medium was monitoredby visual observation ,and the absorption spectrum of fungal filtrate was scanned in the range of 200–800 nm by using UV-Visible spectrophotometer .The UVVisible spectra recorded after 24 hours ofincubation of the fungal filtrate and silver ions showed increase in absorption centered at 400nm.Determination of size and morphology of the silver nanoparticle was determined from the brightfield images by TEM The protein content in the silver nanoparticles was also corroborated by the brightfield images of the silver nanoparticles and by ESI map for S atoms (from the protein).conclusion:In this study, it has been demonstrated that Aspergillus niger is capable ofproducingsilver nanoparticales extracellularly and the silver nanoparticales arequite stable in solution.. SEMsuggests that aggregated particles due to the capping agent.

Biosynthesis, Characterization and Evaluation of Antimicrobial, Antioxidant and Antiproliferiative Activities of Biogenic Silver Nanoparticles Using Streptomyces KBR3

Facile synthesis of silver nanoparticles was attempted using soil derived Streptomyces sp. KBR3 and its antimicrobial, antioxidant and antiproliferiative properties were evaluated in vitro. The extracellular synthesis of silver nanoparticles by the biomass of Streptomyces sp. KBR3 was confirmed through visual color change and ultraviolet-visible spectral analysis. Results of transmission electron microscopy, selected area electron diffraction and X-ray diffraction analysis showed the crystalline polydispersed spherical shaped nanoparticles with the size of 36 nm. Fourier-transform infrared spectroscopy analysis suggested the role of water soluble polyols present in the Streptomyces sp. KBR3 in mediating the synthesis of silver nanoparticles. The synthesized silver nanoparticles showed significant antibacterial activity against Staphylococcus aureus and Escherichia coli. In antioxidant studies, the silver nanoparticles showed maximum scavenging effects of 84 %±1.22 %, 95.8 %±1.32 % and 57.85 %±0.54 % at 1000 μg/ml in 2,2-diphenyl-1-picrylhydrazyl, 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) and metal chelating assay with the half-maximal inhibitory concentration value of 40 μg/ml, 15 μg/ml and 53 μg/ml, respectively. In antiproliferiative study on H357 oral cancer cell line, the silver nanoparticles showed 77.21 %±0.43 % reduction in cell viability at 250 μg/ml with the half-maximal inhibitory concentration values of 9.431 μg/ml. The present study showed that the silver nanoparticles synthesized using the Streptomyces sp. KBR3 might be a promising material for different biomedical applications.

Mouthwash Preparation Using Stevia and Neem Based Silver Nanoparticles and Its Cytotoxic Activity

Introduction: Azadirachta indica (Neem) may be a rapid-growing plant even in severe drought which shed most of its leaves. The branches are wide and spreading. In this present investigation, we have prepared mouthwash using Stevia and Neem-based silver nanoparticles. Materials And Methods: Azadirachta indica and Stevia rebaudiana plant powder form was taken. 1g of Neem and Stevia extract powder mixed with 100ml of distilled water and then it was boiled, cooled and filtered with filtered paper and allowed to settle and the extract mixture was found to be 50ml and filtered. Results And Discussion :The plant had exhibited a potent cytotoxic effect at higher concentrations. Extracellular synthesis of silver nanoparticles using Neem and Stevia was primarily identified by visual identification; the appearance of silver and whitish colour in reaction mixture indicates nanoparticles. Conclusion :The present study revealed that the silver nanoparticles can be synthesised in a simple eco-friendly method using Neem and Stevia .

Green Extracellular Synthesis of Silver Nanoparticles by Pseudomonas alloputida, Their Growth and Biofilm-Formation Inhibitory Activities and Synergic Behavior with Three Classical Antibiotics.

Bacterial resistance to antibiotics is on the rise and hinders the fight against bacterial infections, which are expected to cause millions of deaths by 2050. New antibiotics are difficult to find, so alternatives are needed. One could be metal-based drugs, such as silver nanoparticles (AgNPs). In general, chemical methods for AgNPs' production are potentially toxic, and the physical ones expensive, while green approaches are not. In this paper, we present the green synthesis of AgNPs using two Pseudomonas alloputida B003 UAM culture broths, sampled from their exponential and stationary growth phases. AgNPs were physicochemically characterized by transmission electron microscopy (TEM), total reflection X-ray fluorescence (TXRF), infrared spectroscopy (FTIR), dynamic light scattering (DLS), and X-ray diffraction (XRD), showing differential characteristics depending on the synthesis method used. Antibacterial activity was tested in three assays, and we compared the growth and biofilm-formation inhibition of six test bacteria: Bacillus subtilis, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Staphylococcus aureus, and Staphylococcus epidermidis. We also monitored nanoparticles' synergic behavior through the growth inhibition of E. coli and S. aureus by three classical antibiotics: ampicillin, nalidixic acid, and streptomycin. The results indicate that very good AgNP activity was obtained with particularly low MICs for the three tested strains of P. aeruginosa. A good synergistic effect on streptomycin activity was observed for all the nanoparticles. For ampicillin, a synergic effect was detected only against S. aureus. ROS production was found to be related to the AgNPs' antibacterial activity.

Screening for extracellular synthesis of silver nanoparticles by bacteria isolated from Al-Halfaya oil field reservoirs in Missan province, Iraq

Abstract. Alshami HGA, Al-Tamimi WH, Hateet RR. 2022. Screening for extracellular synthesis of silver nanoparticles by bacteria isolated from Al-Halfaya oil field reservoirs in Missan province, Iraq. Biodiversitas 23: 3462-3470. Microorganisms that live in deep environments are thought to be adapted to the conditions of these environments and possess enzymatic systems that can be useful in scientific and commercial applications. The study aimed to isolate, identify, and screening of silver nanoparticles (AgNPs)-producing bacteria from five samples of produced water of the Al-Halfaya oil field reservoirs in Missan governorate, Iraq. The results revealed a total of 22 bacterial isolates were isolated and identified by morphological features and amplification of the 16S rDNA gene. The isolates are belonging to nine species, including Bacillus cereus strain DBA1.1, Bacillus thuringiensis strain MSP51, Neobacillus drentensis strain ROA042, Enterococcus faecalis strain 2674, Exiguobacterium mexicanum strain AB201, Klebsiella quasipneumoniae strain KP18-31, Klebsiella quasipneumoniae subsp. similipneumoniae strain 2437, Klebsiella pneumoniae strain IOB-L, and Acinetobacter lwoffii strain K34. The Gram-positive bacteria were the most dominant (55.56%), and the most frequent isolate was Klebsiella quasipneumoniae strain KP18-31 (63.64%). Six species out of nine species were recognized as AgNPs producing bacteria and B. cereus strain DBA1 was the best and most potent isolate in the synthesis of AgNPs. The phylogenetic tree was constructed depending on 16S rDNA gene sequences to determine the evolutionary relationship among the isolated bacteria.

Proficient mycogenic synthesis of silver nanoparticles by soil derived fungus Aspergillus melleus SSS-10 with cytotoxic and antibacterial potency

The present study aimed at evaluating the extracellular synthesis of silver nanoparticles by soil fungus Aspergillus melleus SSS-10 for antibacterial and cytotoxic activity. In this study, the formation of silver nanoparticles (AgNPs) was estimated by the colour change in cell free extract from pale yellow to golden yellow after 24 h of the reaction. UV‐Vis study showed the absorbance maxima at 410 nm. Tauc plot analysis revealed the band gap energy as 2.34 eV. Dynamic Light Scattering (DLS) data revealed polydisperse anisotropic silver nanoparticles with average hydrodynamic diameter of 92.006 nm. Zeta potential of − 19.6 mV provided evidence of stable silver nanoparticles. X-ray diffraction (XRD) analysis revealed four prominent Bragg peaks corresponding to (111), (200), (220) and (311) planes characteristic of silver (Ag) in FCC structural configuration. Average crystallite size was found to be 87.3 nm from Scherrer equation. Scanning Electron Microscope (SEM) analysis revealed irregular morphology of silver nanoparticles. EDS analysis displayed characteristic energy peaks of silver from 2.72 keV to 3.52 keV confirming the presence of silver nanoparticles. Biosynthesized AgNPs exhibited strong cytotoxic potential on MG-63 cells. AgNPs also showed antibacterial activity against both Staphylococcus aureus and Escherichia coli. In conclusion, this study provides a platform to explore the utility of fungal mediated silver nanoparticles synthesized for various pharmaceutical and cosmeceutical applications.

Extracellular Synthesis of Silver Nanoparticles Using a Novel Bacterial Strain Kocuria rhizophila BR-1: Process Optimization and Evaluation of Antibacterial Activity

Extracellular Synthesis of Silver Nanoparticles Using a Novel Bacterial Strain Kocuria rhizophila BR-1: Process Optimization and Evaluation of Antibacterial Activity

Aspergillus niger as a Bio-Lab for Extracellular Synthesis of Silver Nanoparticles and Its Antibacterial Activity

Aspergillus niger as a Bio-Lab for Extracellular Synthesis of Silver Nanoparticles and Its Antibacterial Activity

Extracellular synthesis of silver nanoparticles by bioluminescent bacteria: characterization and evaluation of its antibacterial and antioxidant properties

Extracellular synthesis of silver nanoparticles by bioluminescent bacteria: characterization and evaluation of its antibacterial and antioxidant properties

Extracellular Synthesis of Silver Nanoparticles by Soil Isolate of Staphylococcus sp.

Nanoparticles are congregate of atoms ranging in size from 1-100nm. There exists three basic ways of nanoparticle synthesis- physical synthesis, chemical synthesis and green synthesis. The limitations for the first two methods led to the development of green synthesis which is economical and less harmful for the environment. Green synthesis uses living forms like bacteria, virus, fungi, algae as well as plant extracts. Nanoparticles produced from bacteria are based on the principle of microbial metal reduction. The synthesis process can either be extracellular or intracellular depending on the type of microorganisms used. The present study highlights the extracellular synthesis of silver nanoparticles (AgNPs) from soil isolates of Pseudomonas sp. and Staphylococcus sp. The bacterial cultures after isolation were acclimatized in increasing concentration of silver nitrate in growth media and subsequently used for synthesis process. The nanoparticles formed by both the organisms were characterized by UV-Visible Spectrophotometer, FTIR Analysis and Particle size analysis. The absorption maxima for Pseudomonas sp. and Staphylococcus sp. cell free extracts were obtained at 410 and 400nm which approximately corresponds to the size range of 20-40 nm and 10-20 nm, respectively. Though there are several reports related to Pseudomonas sp. being used for nanoparticle synthesis, there are very few reports related to the Staphylococcus sp. being used for the same. The study clearly indicates the capability of Staphylococcus sp. to form nanoparticles with physical properties comparable to the Pseudomonas sp.

BIOSYNTHESIS OF SILVER AND COPPER NANOPARTICLES BY MYCELIAL FUNGI

The possibility of the synthesis of silver and copper nanoparticles by strains of fungi of Phanerochaete, Penicillium and Fusarium has been tested. Cultures that were capable of forming nanoparticles have been identified. As a result of the experiments 4 cultures were selected (Ph. chrysosporium БИМ F-110, P. decumbens ЛФ F-1, F. oxysporum ЛФ F-1, F. oxysporum БИМ F-447), capable of extracellular synthesis of silver nanoparticles, characterized by stability during 5–6 days.

Cyto-genotoxicity, antibacterial, and antibiofilm properties of green synthesized silver nanoparticles using Penicillium toxicarium.

The fungi are becoming the distinguished organisms utilized in the biological synthesis of metallic nanoparticles because of their metal bioaccumulation ability. Addressed herein, the extracellular synthesis of silver nanoparticles (AgNPs) was carried out by using the cell-free filtrate of Penicillium toxicarium KJ173540.1. P. toxicarium was locally isolated and identified using both classical and molecular methods according to ribosomal internal transcribed spacer area of 18S rDNA. The optimum conditions for the AgNPs synthesis were found as 0.25 mM AgNO3 concentrations with pH 12 values at 45°C after 64 hr incubation in dark. Biosynthesized AgNPs were characterized via microscopic and spectroscopic techniques such as transmission electron microscopy, scanning electron microscopy, energy dispersive X-ray analysis, Fourier transform infrared spectrophotometer, and ultraviolet-visible spectroscopy. Zetasizer measurements presented that the high negative potential value (-18.1 mV) and PDI (0.495) supported the excellent colloidal nature of AgNPs with long-range stability and high dispersity. AgNPs exhibited cyto-genotoxicity in Allium cepa root meristem cells by decreasing mitotic index and increasing chromosome aberrations in a dose-dependent manner. Then, 100 and 50% concentration of biosynthesized AgNPs showed antibacterial activity on Staphylococcus aureus and Bacillus subtilis. A decreasing biofilm formation of Pseudomonas aeruginosa 80.69, 48.32, and 28.41% was also observed at 100, 50, and 25% of mycosynthesized AgNP, respectively.

Biosynthesis and Characterization of Silver Nanoparticles Using Wheatgrass Extract and Assessment of Their Anticandidal Activity

Wheatgrass extract was used for eco-friendly extracellular synthesis of silver nanoparticles. Stable silver nanoparticles were formed by treating the wheatgrass extract with aqueous silver nitratesolution as reducing agents. Ultraviolet–visible spectroscopy was used to confirm the presence of silver nanoparticles. The X-ray diffraction analysis exhibited characteristic peaks signifying the crystalline nature of nanoparticels. The particle size and the involvement of various biomolecules in the synthesis of silver nanoparticles were determined using Atomic force microscopy and Fourier transform infrared spectroscopy, respectively. The particle structure was studied by scanning electron microscopy and the elemental silver present in reaction mixture was confirmed by Energy dispersive x-ray. The nanoparticles were tested for their anticandidal activity against Candida albicans MTCC3017, Candida albicans MTCC1637, Candida albicans MTCC183, Candida tropicalis MTCC230 and Candida glabrata MTCC3814 and determined their minimum inhibitory concentration.

Biogenically proficient synthesis and characterization of silver nanoparticles employing marine procured fungi Aspergillus brunneoviolaceus along with their antibacterial and antioxidative potency.

To assess the extracellular synthesis of silver nanoparticles using marine derived fungi Aspergillus brunneoviolaceus with their antibacterial and antioxidant activities. The biosynthesis of silver nanoparticles was estimated by the change in color from light yellow to dark brown within 36h as the reaction progressed. UV-Visible spectroscopy exhibited its stability at 411nm; ATR-FTIR spectroscopy depicted the functional group responsible for its production; X-Ray Diffraction denoted its crystalline FCC structure resembling the peaks in XRD pattern, corresponding to [111], [200], [220], [311] and [222] planes; TEM imaging revealed its spherical morphology with the particle size ranging from 0.72 to 15.21nm and Tauc's plot analysis that disclosed its band gap energy as 2.44eV that manifested the potential of AgNPs to be semiconductors. The characterization data henceforth, confirmed the efficient production of silver nanoparticles. The biosynthesized AgNPs expressed strong antibacterial activity against two Gram-positive and three Gram-negative bacteria. They also proved to possess higher antioxidative potentials by showing their potent radical scavenging activity against DPPH (2, 2-diphenyl-1-picrylhydrazyl). The study unfolds the prospect for further utilization of this mycogenically synthesized AgNPs as antibacterial, antioxidative and anticancer agents.

Anti-Bacterial and Anti-Candidal Activity of Silver Nanoparticles Biosynthesized Using Citrobacter spp. MS5 Culture Supernatant.

The present study described the extracellular synthesis of silver nanoparticles (AgNPs) using environmental bacterial isolate Citrobacter spp. MS5 culture supernatant. To our best knowledge, no previous study reported the biosynthesis of AgNPs using this bacterial isolate. The biosynthesized AgNPs were characterized using different techniques like UV-Vis spectroscopy, fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM) equipped with energy dispersive X-ray (EDX). The analysis of UV-Vis spectra revealed absorption maxima at 415 nm due to surface plasmon resonance (SPR) indicated the formation of AgNPs and FTIR spectrum confirmed the participation of proteins molecule in AgNPs synthesis. XRD and EDX spectrum confirmed the metallic and crystalline nature of AgNPs. TEM and SEM showed spherical nanoparticles with a size range of 5–15 nm. The biosynthesized AgNPs showed effective independent as well as enhanced combined antibacterial activity against extended spectrum β-lactamase (ESBL) producing multidrug resistant Gram-negative bacteria. Further, effective antifungal activity of AgNPs was observed towards pathogenic Candida spp. The present study provides evidence for eco-friendly biosynthesis of well-characterized AgNPs and their potential antibacterial as well as antifungal activity.

Extracellular synthesis of silver nanoparticles by Thiosphaera pantotropha and evaluation of their antibacterial and cytotoxic effects.

Extracellular biosynthesis of silver nanoparticles (AgNPs) was explored using Thiosphaera pantotropha since this strain exhibits both nitrate- and nitrite-reductase enzyme activity (NaR and NiR, respectively). Optimal AgNP synthesis was achieved using 2mM AgNO3, culture supernatant of nutrient broth grown T. pantotropha, and incubation at 37°C and 180rpm. Under these conditions, the localized surface plasmon resonance peak of silver at 404nm matched well with the average size of the spherical AgNPs based on FEG-TEM micrographs, i.e., 14.6nm (range: 5-51nm). The zeta potential of -33.6mV indicated good stability of the biosynthesized nanoparticles. The XRD spectra demonstrated the simultaneous presence of face-centered cubic crystal structure of AgNPs and AgCl NPs. Ag+ ions were possibly reduced by the NaR and NiR enzymes released into the culture media. The FTIR spectra confirmed the stabilization of the AgNPs by biomolecules present in the culture supernatant of T. pantotropha. The synthesizedAg/AgCl NPs exhibited good antibacterial efficacy against both Gram-negative (Escherichia coli and Pseudomonas aeruginosa) and Gram-positive bacteria (Bacillus subtilis and Staphylococcus aureus). The minimum inhibitory concentration (MIC) was 2.5µg/ml for all the bacteria except B. subtilis (MIC of 10µg/ml). The minimum bactericidal concentration (MBC) was 2.5, 10, 20, and 5µg/ml for E. coli, P. aeruginosa, B. subtilis, and S. aureus, respectively. At MBC and higher AgNP concentration, both plating and CLSM imaging confirmed the absence of viable bacteria in treated water. The biogenic AgNPs depicted IC50 of 34.8µg/ml for MCF-7 cells.

Extracellular Synthesis and Characterization of Silver Nanoparticles-Antibacterial Activity against Multidrug-Resistant Bacterial Strains.

Herein, we report the use of a cell-free extract for the extracellular synthesis of silver nanoparticles (AgNPs) and their potential to address the growing threat of multidrug-resistant (MDR) pathogenic bacteria. The reproducibility of AgNP synthesis was good and AgNP formation kinetics were monitored as a function of various reaction factors via ultraviolet-visible absorption spectroscopy. This green method was dependent on the alkaline pH of the reaction mixture. With the addition of dilute sodium hydroxide, well-dispersed AgNPs could be produced in large quantities via the classical nucleation and growth route. The new biosynthetic route enabled the production of AgNPs within a narrow size range of 4 to 17 nm. The AgNPs were characterized using various techniques and their antibacterial activity against MDR pathogenic bacteria was evaluated. Field-emission scanning electron microscopic imaging revealed prominent morphological changes in Staphylococcus aureus cells due to mechanical damage, which led to cell death. Escherichia coli cells showed signs of contraction and intracellular fluid discharge as a consequence of disrupted cell membrane function. This new biologically-assisted extracellular strategy is potentially useful for the decontamination of surfaces and is expected to contribute to the development of new products containing AgNPs.

Extracellular synthesis of silver nanoparticles by Acinetobacter baumanii and antibacterial characterization

Extracellular synthesis of silver nanoparticles by Acinetobacter baumanii and antibacterial characterization

Extracellular synthesis of silver nanoparticles using entomopathogenic fungus: characterization and antibacterial potential

Present study involves the simple, rapid, non-toxic and in vitro method of extracellular silver nanoparticles synthesis using Entomopathogenic fungus (Beauveria bassiana). The development of silver nanoparticle in fungal supernatant was confirmed by the absorbance peak at 450 nm in UV–Vis spectrophotometer. Further, presence of AgNPs and its crystal lattice was confirmed by EDS and XRD, respectively. TEM micrograph confirmed the presence of differently shaped (triangular, circular, hexagonal) nanoparticles with size ranging from 10 to 50 nm. Variable shape and size of fungal assisted AgNps was also confirmed in SEM study. The optimal pH and temperature for biosynthesis of nanoparticles was found to be 6.0 and 25 °C, respectively. The continuous effects of AgNPs against Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus in time dependent manner was confirmed in growth kinetic studies. During 36 h of growth study, maximum reduction in O.D560 was found in E. coli (67.2%) followed by P. aeruginosa (63.3%) and S. aureus (56.8%) at 30 °C. The MIC values of fungal assisted AgNPs against E. coli, P. aeruginosa and S. aureus was found to be 2.5, 3 and 4.5 ppm, respectively. The MIC values of Ciprofloxacin was observed to be 0.5, 0.5 and 0.7 ppm, whereas MICs of AgNPs + Ciprofloxacin showed 0.4, 0.4, 0.5 ppm against E. coli, P. aeruginosa and S. aureus, respectively, clearly highlighting the synergistic effect of AgNPs in combination with Ciprofloxacin. In the view of challenges for developing antimicrobial nanoparticles of variable shape and size by various other methods, tuning nanoparticles synthesis via fungi can be a wonderful approach to resolve existing hurdles.

Extracellular Mycosynthesis of Antibacterial Silver Nanoparticles UsingAspergillus flavusand Evaluation of their Characteristics

Fungi extracellular synthesis of silver nanoparticles (AgNPs) using Aspergillus flavus mycelia extract was evaluated. Fourier transform-infrared spectroscopy revealed the presence of hydroxyl and amide I groups in the prepared fungi mycelia extract which those had key roles in the reduction of silver ions and stabilizing of the formed AgNPs. Response surface methodology (RSM) has been used to optimize and evaluate the effects of the prepared mycelia extract amount (5–7[Formula: see text]mL) and autoclave heating time (10–20[Formula: see text]min) on the particle size of the synthesized AgNPs. Obtained results revealed that the spherical mono-dispersed AgNPs with high stability were synthesized using 6[Formula: see text]mL of fungal mycelia extract and hydrothermally heating for 15[Formula: see text]min. At this obtained optimum synthesis conditions, broad emission peaks ([Formula: see text], mean particle size, concentration and zeta potential values for the fabricated AgNPs were 450[Formula: see text]nm, 44[Formula: see text]nm, 72[Formula: see text]ppm and [Formula: see text][Formula: see text]mV, respectively. The synthesized AgNPs also indicated high antibacterial activity against both Gram positive and negative bacteria.