Biosynthesis Of AgNPs Research Articles

Rumex nervosus mediated green synthesis of silver nanoparticles and evaluation of its in vitro antibacterial, and cytotoxic activity

In the present study, we have reported the low-cost, green synthesis of silver nanoparticles using Rumex nervosus (Rn) leaf extract. The biological synthesis of Rn-AgNPs employing plant extracts has become an optimistic substitute for the conventional chemical method of synthesis. Initially, the synthesis of Rn-AgNPs was explained by the optical study of the color change in the mixture. The biosynthesized AgNPs were characterized by UV-visible absorption spectroscopy, FTIR analysis, EDX, zeta potential, and DLS. TEM revealed that most of the Rn-AgNPs are spherical/oblong in shape with the average particle size falling in the range of 20-70 nm. The green synthesized Rn-AgNPs showed potent antibacterial and antibiofilm activity against the gram-negative (Escherichia coli) and gram-positive (Staphylococcus aureus) bacteria. The cytotoxicity assays of as-formed AgNPs exhibited minimal toxicity to human RBCs and PBMCs. Hence, these nanoparticles are considered non-toxic for use as drugs in biomedicine.

Eco-friendly Green Synthesis of Silver Nanoparticles from Leaf Extract of Solanum khasianum: Optical Properties and Biological Applications.

The green synthesis of silver nanoparticles (AgNPs) was considered to be efficacious over other approaches due to their eco-friendliness, cost-effectiveness, and high stability. The biosynthesis of AgNPs was achieved by the reduction of silver nitrate using the aqueous leaf extract of Solanum khasianum. The biosynthesized AgNPs were examined by a color change and UV-Vis spectroscopy with an absorption spectrum at 440nm. The biomolecules existing in S. khasianum leaf extract accountable for bioreduction and capping of AgNPs were analyzed by FTIR analysis and confirmed the presence of alcohols, phenols, alkanes, carboxylic acid, nitro compounds, and amines. The crystalline nature of Sk-AgNPs with face-centered cubic lattice was confirmed by X-ray diffraction (XRD) spectrum. The average crystallite size of Sk-AgNPs was computed as 15.96nm. The lattice constant, unit cell volume, and spacing values of Sk-AgNPs were parallel to the values indexed in the Joint Committee on Powder Diffraction Standard of silver (JCPDS-04-0783). Scanning electron microscope (SEM) imaging witnessed the spherical structure of synthesized AgNPs. Energy dispersive X-ray (EDX) spectrum acknowledged the AgNPs fabrication with strong signals of silver atoms at 3keV energy. The biofabricated Sk-AgNPs showed a photoluminescence (PL) emission spectrum of 445nm with an excitation at 330nm. Sk-AgNPs showed considerable DPPH radical scavenging activity (87.98%) than BHT (86.14%) and also exhibited significant antidiabetic activity compared to acarbose. Sk-AgNPs revealed antibacterial potentiality against B. sphaericus, E. coli, S. aureus, and P. fluorescens. Moreover, Sk-AgNPs showed dose-dependent cytotoxicity against MCF-7 cell line. This method of green synthesis would support the eco-friendly fabrication of AgNPs from S. khasianum leaf extract with considerable therapeutic activities.

Green synthesis and anticancer activity of silver nanoparticles prepared using fruit extract of Azadirachta indica

Effective cancer therapies with limited side effects are urgently needed, for which silver nanoparticles (AgNPs) have shown potential. However, environmentally friendly methods for preparing AgNPs require improvements. In this study, we biologically synthesized AgNPs using the fruit extract of Azadirachta indica, an effective medicinal plant used to treat various diseases. Medicinal Plants contain phytochemicals, such as polyphenols, flavonoids, and tannins, that function as reducing and stabilizing agents and are therefore suitable for application in biological methods for synthesis. The study proposes a new approach involving the combination of the biosynthesized AgNPs with cisplatin (AgNP-cis). The biosynthesized AgNPs were characterized using various methods, and their cytotoxicity against the A549 cell line was examined. Ultraviolet–visible spectroscopy revealed surface plasmon resonance bands at 429 and 435 nm for AgNPs and AgNP-cis, respectively. The results from the AgNPs morphology evaluation showed that the NPs were spherical with diameters of 27 nm. Dynamic light scattering analysis revealed an average diameter of 249 and 260 nm for AgNPs and AgNPs-cis, respectively. Zeta potential measurements showed that AgNPs were colloidally stable at −35.6 mV, and the zeta potential for AgNPs-cis was −22 mV. Fourier transform infrared spectroscopy confirmed the embedding of biomolecules, such as polyphenols and flavonoids, in the surfaces of both AgNPs and AgNPs-cis. The synthesized AgNPs were highly toxic against A549 lung cancer cells in vitro. Furthermore, our study demonstrates stable AgNPs with a desirable morphology and high yield, thereby improving the AgNPs properties for various medicinal applications.

Synergistic Antibacterial Effect from Silver Nanoparticles and Anticancer Activity Against Human Lung Cancer Cells

Microbially synthesized silver nanoparticles (AgNPs) with high stability and bioactivity have recently shown considerable promise in biomedical research and application. In this study, AgNPs prepared by Penicillium aculeatum Su1 exhibited effective antibacterial action by inhibiting bacterial growth and destroying cellular structure. Meanwhile, their assessed increased in fold area (IFA) through the Kirby-Bauer disc diffusion method proved that, the AgNPs showed synergistic antibacterial effect on different bacteria when combined with antibiotics, especially for drug-resistant P. aeruginosa (4.58∼6.36-fold) and B. subtilis (4.2-fold). Moreover, the CCK-8 assay and flow cytometric analysis were used to evaluate the cytotoxic effects of AgNPs on normal cells (HBE) and lung cancer cells (HTB-182), which confirmed that they presented higher biocompatibility towards HBE cells when compared with silver ions, but high cytotoxicity in a dosedependent manner with an IC50 values of 35.00 μg/mL towards HTB-182 cells by raising intracellular reactive oxygen species (ROS) levels, hindering cell proliferation, and ultimately leading to cell cycle arrest and cell apoptosis. These results demonstrate that, the biosynthesized AgNPs could be a potential candidate for future therapies of infection caused by drug-resistant bacteria, as well as lung squamous cell carcinoma.

Ginger (Zingiber officinale) extract mediated green synthesis of silver nanoparticles and evaluation of their antioxidant activity and potential catalytic reduction activities with Direct Blue 15 or Direct Orange 26.

The green synthesis of silver nanoparticles (AgNPs) using a water extract of Ginger (Zingiber officinale) root by microwave irradiation and its antibacterial activities have been reported. However, AgNPs prepared from different parts of ginger root water or ethanol extract by ultrasound synthesis and their antioxidant activity and whether the biogenic could be used to catalyze the reduction of hazardous dye are unknown. This study concentrated on the facile green synthesis of AgNPs prepared from different parts (unpeeled ginger, peeled ginger, and ginger peel) of ginger root water or ethanol extract by the ultrasound-assisted method. We studied their antioxidant activity and catalytic degradation of hazardous dye Direct Orange 26 (DO26) and Direct Blue 15 (DB15). The surface plasmon resonance (SPR) peak of AgNPs was at 428–443 nm. The biogenic AgNPs were approximately 2 nm in size with a regular spherical shape identified from TEM analysis. The ethanol extracts of dried unpeeled ginger and peeled ginger, fresh peeled ginger and ginger peel. The Z. officinale AgNPs synthesized by dried unpeeled ginger ethanol extract showed the best antioxidant activity. Their scavenging activities were significantly better than BHT (p <0.05). The different parts of ginger extracts showed no catalytic degradation activities of DB15 and DO26. Still, the synthesized Z. officinale AgNPs exhibited good catalytic degradation activities, while their ability to catalytic degradation to DB15 was better than DO26. In the additive ratio of 3 mL DB15, 0.1 mL NaBH4 and 0.1 mL AgNPs, the degradation rates of DB15 (or DO26) at 15 min, 30 min and 60 min were only 1.8% (0.9%), 2.8% (1.4%) and 3.5% (1.6%) in the absence of AgNPs. When adding Z. officinale AgNPs prepared from dried ginger peel ethanol extract or fresh ginger peel water extract, the degradation rates of DB15 sharply increased to 97% and 93% after 30 min, respectively. In conclusion, ginger extract has good antioxidant properties. Z. officinale AgNPs biosynthesis from ginger extract exhibit excellent catalytic degradation activities, especially for the ginger peel extract. They have application value in the treatment of textile effluents and provide a new idea and method for the comprehensive development and utilization of ginger resources.

Biogenesis and characterization of proficient silver nanoparticles employing marine procured fungi Hamigera pallida and assessment of their antioxidative, antimicrobial and anticancer potency.

To assess the anticancer potential of biosynthesized silver nanoparticles using marine derived fungi Hamigera pallida with their antibacterial and antioxidant activities. The biosynthesis of silver nanoparticles (AgNPs) was assessed by the change in color from bright yellow to dark brown. UV-Visible spectroscopy revealed its stability at 429nm; ATR-FTIR spectroscopy revealed the functional group responsible for its production; X-Ray Diffraction revealed its crystalline FCC structure resembling the peaks in the XRD pattern, corresponding to (110), (111), (200), and (311) planes; TEM imaging revealed its spherical morphology with an average particle size of 5.85 ± 0.84nm ranging from 3.69 to 16.11nm and Tauc's plot analysis revealed a band gap energy of 2.22eV, revealing aptitude of AgNPs as a semiconductors. The subsequent characterization results revealed the effective synthesis of silver nanoparticles. The biosynthesized AgNPs were found to have significant antimicrobial effect against three Gram-positive and three Gram-negative bacteria. They also demonstrated higher antioxidative potential by demonstrating strong radical scavenging activity against DPPH (2, 2-diphenyl-1-picrylhydrazyl). AgNPs showed highest anticancer activity (62.69 ± 1.73%) against human breast cancer (MCF-7) cell line at 100µg/mL with the IC50 value of 66.07 ± 2.17µg/mL. This study revealed the prospect for further utilization of AgNPs by Cell free filtrate of Hamigera pallida as an antibacterial, antioxidative and anticancer agents.

Bioreduction and Stabilization of Nanosilver using Chrysanthemum Phytochemicals for Antibacterial and Wastewater Treatment

AbstractAn easy, sustainable, and one‐step method has been explored to synthesize colloidal silver nanoparticles (AgNPs) using Chrysanthemum (CT) flower extract and applied for antibacterial treatment and azo dye catalysis. The synthesis parameters (effect of CT extract concentration, reaction temperature, time, and pH) were thoroughly examined via a one‐variable‐at‐a‐time (OVAT) method to identify an optimization condition. The characterization of AgNPs produced at as‐obtained optimum condition found that the nanoparticles are primarily spherical/oval shape, nanometer size (1.98±0.57 nm), very crystalline (d‐spacing=0.236 nm), significantly stabilized (zeta potential=−22.1 mV). The characterizations also indicated that the AgNPs were produced by the redox reaction between plant phytochemicals and metal cations and stabilized via encapsulation of plant phytochemicals. The bacterial resistivity AgNPs was monitored by the agar disk diffusion test and found to be highly effective towards both Staphylococcus aureus (+ev) and Escherichia coli (−ev) bacteria. Moreover, the synthesized AgNPs displayed an innate catalytic reduction of azo dyes such as acid red 1 (AR1) and acid blue 29 (AB29). The degradation reactions were followed pseudo‐first‐order kinetics model and the rate constants k were calculated to be 0.45528 min−1 (r2=0.94465) for AR1 and 0.28214 min−1 (r2=0.88764) for AB29, respectively. This study reveals the prospect of CT flower extract as a botanical source for the biosynthesis of AgNPs and its potential application in bacterial reduction and azo‐contaminated wastewater treatment.

Biogenic synthesis of silver nanoparticles mediated by the consortium comprising the marine fungal filtrates of Penicillium oxalicum and Fusarium hainanense along with their antimicrobial, antioxidant, larvicidal and anticancer potency.

To biosynthesize silver nanoparticles (AgNPs) using fungal isolates [DS-2 (Penicillium oxalicum) and DW-8 (Fusarium hainanense)] as well as their mixed cell-free filtrate (CFF) acting as a consortium (DSW-28) and their bio-potentials. The fungi (DS-2 and DW-8) were harvested and CFF was prepared. CFF of each fungus and their mixture were reacted with silver nitrate solution under dark conditions for the synthesis of AgNPs. The UV-Visible spectra determined the surface plasmon resonance at 438, 441 and 437 nm for the AgNPs synthesized by DS-2, DW-8 and DSW-28, respectively. The band gap energy was found between 2.21 and 2.24 eV which depicted their ability to act as a semiconductor. The TEM imaging revealed the spherical shape and small size of AgNPs. The XRD pattern exhibited the crystalline structure corresponding to their peaks. The FTIR spectra indicate the presence of different functional groups present on the surface of AgNPs. The broad-spectrum antimicrobial activity was exhibited by AgNPs. The AgNPs also act as an effective antioxidant by depicting their radical scavenging activity against DPPH. Moreover, the AgNPs also inhibited the growth of fourth instar larvae of Aedes aegypti and Culex quinquefasciatus more efficiently in a dose-dependent method. The biosynthesized AgNPs from DSW-28 showed a significant anticancer activity against MCF-7 cells. The silver nanoparticles synthesized by the CFF of two different fungi act synergistically in a consortium leading towards the production of silver nanoparticles with smaller size and higher bioactivity. The impressive bioactivity of the silver nanoparticles synthesized by the mixture of CFF of various fungi acting as a consortium recommends their prospective use in agriculture as well as in biomedical as an antimicrobial, antioxidant, larvicidal and anticancer agents in future.

Biomedical and catalytic applications of agri-based biosynthesized silver nanoparticles

Nanotechnology has been recognized as the emerging field for the synthesis, designing, and manipulation of particle structure at the nanoscale. Its rapid development is also expected to revolutionize industries such as applied physics, mechanics, chemistry, and electronics engineering with suitably tailoring various nanomaterials. Inorganic nanoparticles such as silver nanoparticles (Ag-NPs) have garnered more interest with their diverse applications. In correspondence to green chemistry, researchers prioritize green synthetic techniques over conventional ones due to their eco-friendly and sustainable potential. Green-synthesized NPs have proven more beneficial than those synthesized by conventional methods because of capping by secondary metabolites. The present study reviews the various means being used by the researchers for the green synthesis of Ag-NPs. The morphological characteristics of these NPs as obtained from numerous characterization techniques have been explored. The potential applications of bio-synthesized Ag-NPs viz. Antimicrobial, antioxidant, catalytic, and water remediation along with the plausible mechanisms have been discussed. In addition, toxicity analysis and biomedical applications of these NPs have also been reviewed to provide a detailed overview. The study signifies that biosynthesized Ag-NPs can be efficiently used for various applications in the biomedical and industrial sectors as an environment-friendly and efficient tool.

The effect of AgNPS bio-functionalization on the cytotoxicity of the yeast Saccharomyces cerevisiae.

This work used Sedum praealtum leaf extract to synthesize silver nanoparticles (AgNPs) in a single step. The cytotoxicity of AgNPs was studied with the yeast Saccharomyces cerevisiae W303-1. In addition, the antioxidant activity of the DPPH radical was studied both in the extract of S. praealtum and in the AgNPs. UV-Vis spectroscopy determined the presence of AgNPs by the location of the surface plasmon resonance (SPR) band at 434nm. TEM and XRD analyzes show AgNPs with fcc structure and hemispherical morphology. Also, AgNPs range in size from 5 to 25nm and have an average size of 14nm. 1H NMR, FTIR, and UV-Vis spectroscopy techniques agreed that glycosidic compounds were the main phytochemical components responsible for the reduction and stabilization of AgNPs. In addition, AgNPs presented a maximum of 12% toxicity in yeast attributed to the generation of ROS. Consequently, there was low bioactivity because glycoside compounds cover the biosynthesized AgNPs from S. praealtum. These findings allow applications of AgNPs involving contact with mammals and higher organisms.

Synthesis and Biological Characterization of Phyto-Fabricated Silver Nanoparticles fromAzadirachta indica

Nanoparticles (NPs) have garnered a lot of interest in sectors like medicine, cosmetics, food, and pharmaceuticals for antibacterial catalytic properties, reduced toxicity, and easy production. Biological synthesis of silver nanoparticle (AgNPs) is considered as green, eco-friendly, and cost-effective approach; therefore,Azadirachta indicaextracts were utilized for a dual role of fabrication and functionalization of AgNPs. Optical and physical characterizations were achieved for confirming the biosynthesized AgNPs. SEM images detected quasi-spherical AgNPs of 44.04 to 66.50 nm. Some of potent phytochemicals like flavonoids and proteins fromAzadirachta indicaformed a strong coating or capping on the AgNPs without affecting their secondary structure by interacting with Ag+and NPs for the formation of AgNPs. AgNPs exhibited strong antibacterial activity (MIC 10μg/ml) against multidrug-resistant bacteriaEnterococcus faecalis; at different concentrations, no IC50 values were recorded for AgNPs as well asAzadirachta indicasignifying low cytotoxicity in the exposed concentration range. The DNA degradation activity of AgNPs through the TUNEL assay revealed no significant increase in the overall FITC mean fluorescence intensity as well as a DNA fragmentation index with 5.45% DNA damage (10μg/ml AgNPs). Drug uptake of AgNPs was also investigated through a permeability assay via Caco-2 cell lines at test concentrations where apparent permeability was detected as moderate.

Synergistic Antibacterial Activity of Green Synthesized Silver Nanomaterials with Colistin Antibiotic against Multidrug-Resistant Bacterial Pathogens

The high frequency of nosocomial bacterial infections caused by multidrug-resistant pathogens contributes to significant morbidity and mortality worldwide. As a result, finding effective antibacterial agents is of critical importance. Hence, the aim of the present study was to greenly synthesize silver nanoparticles (AgNPs) utilizing Salvia officinalis aqueous leaf extract. The biogenic AgNPs were characterized utilizing different physicochemical techniques such as energy-dispersive X-ray spectroscopy (EDX), ultraviolet-visible spectrophotometry (UV-Vis), X-ray diffraction analysis (XRD), transmission electron microscopy (TEM), and Fourier transform infrared spectroscopy (FT-IR) analysis. Additionally, the synergistic antimicrobial effectiveness of the biosynthesized AgNPs with colistin antibiotic against multidrug-resistant bacterial strains was evaluated utilizing the standard disk diffusion assay. The bioformulated AgNPs revealed significant physicochemical features, such as a small particle size of 17.615 ± 1.24 nm and net zeta potential value of −16.2 mV. The elemental mapping of AgNPs revealed that silver was the main element, recording a relative mass percent of 83.16%, followed by carbon (9.51%), oxygen (5.80%), silicon (0.87%), and chloride (0.67%). The disc diffusion assay revealed that AgNPs showed antibacterial potency against different tested bacterial pathogens, recording the highest efficiency against the Escherichia coli strain with an inhibitory zone diameter of 37.86 ± 0.21 mm at an AgNPs concentration of 100 µg/disk. In addition, the antibacterial activity of AgNPs was significantly higher than that of colistin (p ≤ 0.05) against the multidrug resistant bacterial strain namely, Acinetobacter baumannii. The biosynthesized AgNPs revealed synergistic antibacterial activity with colistin antibiotic, demonstrating the highest synergistic percent against the A. baumannii strain (85.57%) followed by Enterobacter cloacae (53.63%), E. coli (35.76%), Klebsiella pneumoniae (35.19%), Salmonella typhimurium (33.06%), and Pseudomonas aeruginosa (13.75%). In conclusion, the biogenic AgNPs revealed unique physicochemical characteristics and significant antibacterial activities against different multidrug-resistant bacterial pathogens. Consequently, the potent synergistic effect of the AgNPs–colistin combination highlights the potential of utilizing this combination for fabrication of highly effective antibacterial coatings in intensive care units for successful control of the spread of nosocomial bacterial infections.

Phytosynthesis, antimicrobial and catalytic activities of silver nanoparticles derived using leaf and stem extracts of Indigofera macrophylla

Background: The phytosynthesis of metal nanoparticles is a promising green alternative to traditional chemical approaches.Objective: The aim of this study was to synthesize silver nanoparticles (AgNPs) with antimicrobial and biocatalytic activities using aqueous leaf and stem extracts of Indigofera macrophylla.Methods: Critical reaction variables for the biosynthesis of AgNPs were optimized using UV-vis spectroscopy before the biosynthesised AgNPs were characterized using various spectroscopic and microscopic techniques. The biological activities of the biogenic nanoparticles were then investigated with particular focus on their antimicrobial activity and biocatalytic efficiency in the degradation of methylene blue.Results: The surface plasmon resonance of silver nanoparticles biosynthesized using aqueous extracts of leaf (LE-AgNPs) and stem (SE-AgNPs) of I. macrophylla occurred at 430 and 426 nm respectively. Scanning electron microscopy images of the nanoparticles showed highly aggregated polymorphs with mostly spherical shape. The particle sizes of LE-AgNPs and SE-AgNPs as determined by Transmission electron microscopy were 48.61±8.60 and 18.09±4.13 nm respectively with Energy dispersive X-ray analysis confirming characteristic absorption band at 3 KeV. In susceptibility assays, LE-AgNPs showed dose-dependent zones of inhibition against Escherichia coli (18 mm), Staphylococcus aureus (18 mm), Pseudomonas aeruginosa (20 mm) while SE-AgNP was only active against Staphylococcus aureus (10 mm). Both LE-AgNPs and SE-AgNPs showed good biocatalytic efficiency in the degradation of methylene blue with rate constants of 0.0204 and 0.0182 min-1 respectively.Conclusion: Silver nanoparticles with antimicrobial and catalytic activities have been biosynthesized using the aqueous extract of Indigofera macrophylla.

Biological Synthesis of Silver Nanoparticles and Prospects in Plant Disease Management.

Exploration of nanoparticles (NPs) for various biological and environmental applications has become one of the most important attributes of nanotechnology. Due to remarkable physicochemical properties, silver nanoparticles (AgNPs) are the most explored and used NPs in wide-ranging applications. Also, they have proven to be of high commercial use since they possess great chemical stability, conductivity, catalytic activity, and antimicrobial potential. Though several methods including chemical and physical methods have been devised, biological approaches using organisms such as bacteria, fungi, and plants have emerged as economical, safe, and effective alternatives for the biosynthesis of AgNPs. Recent studies highlight the potential of AgNPs in modern agricultural practices to control the growth and spread of infectious pathogenic microorganisms since the introduction of AgNPs effectively reduces plant diseases caused by a spectrum of bacteria and fungi. In this review, we highlight the biosynthesis of AgNPs and discuss their applications in plant disease management with recent examples. It is proposed that AgNPs are prospective NPs for the successful inhibition of pathogen growth and plant disease management. This review gives a better understanding of new biological approaches for AgNP synthesis and modes of their optimized applications that could contribute to sustainable agriculture.

Characterization of the biosynthesized intracellular and extracellular plasmonic silver nanoparticles using Bacillus cereus and their catalytic reduction of methylene blue

The biosynthesis of silver nanoparticles (Ag NPs) has been studied in detail using two different approaches. For the first time, Bacillus cereus is used for one-pot biosynthesis of capsulated Ag NPs, using both intracellular and extracellular approaches. To discriminate between the produced nanostructures by these two approaches, their structures, nanomorphologies, optical properties, hydrodynamic sizes and zeta potentials are studied using different techniques. Fourier-transform infrared spectroscopy was used to identify the bioactive components responsible for the reduction of Ag+ ions into Ag and the growth of stable Ag NPs. Scanning and transmission electron microscopy images displayed spherical and polygon nanomorphology for the intracellular and extracellular biosynthesized Ag NPs. For intracellular and extracellular biosynthesized Ag NPs, a face-centred cubic structure was observed, with average crystallite sizes of 45.4 and 90.8 nm, respectively. In comparison to the noncatalytic reduction test, the catalytic activities of intracellular and extracellular biosynthesized Ag NPs were explored for the reduction of highly concentrated MB dye solution. Extracellular Ag NPs achieved 100% MB reduction efficacy after around 80 min, compared to 50.6% and 24.1% in the presence and absence of intracellular Ag NPs, respectively. The rate of MB reduction was boosted by 22 times with the extracellular catalyst, and by 3 times with the intracellular catalyst. Therefore, the extracellular production process of Ag NPs utilizing Bacillus cereus bacteria might be applied in the industry as a cost-effective way for eliminating the toxic MB dye.

Antimicrobial, antibiofilm potential, and anti-quorum sensing activity of silver nanoparticles synthesized from Cyanobacteria Oscillatoria princeps.

Cyanobacteria are among the beneficial and environmentally friendly natural candidates used in the biosynthesis of nanoparticles, with their ability to accumulate heavy metals from their environment, thanks to their biologically active compounds. In the current study, an aqueous extract of Oscillatoria princeps fresh biomass was used for the green synthesis of AgNPs. UV-vis spectrum, Fourier transforms infrared, scanning electron microscopy, and energy-dispersive spectroscopy were used to validate and characterize biosynthesized of OSC-AgNPs. The biosynthesis of AgNPs was visually verified in terms of the change in the color of the AgNO3 solution from yellowish brown to brown colors from 72h onwards. An absorption peak of approximately 420nm was detected in the UV-vis spectrum, corresponding to the plasmon resonance of AgNPs. FT-IR analysis showed the presence of free amino groups in addition to sulfur-containing amino acid derivatives that act as stabilizing agents. SEM images detected the roughly spherical shape of OSC-AgNPs with an average size of 38nm. The pathogens tested were all susceptible to OSC-AgNPs showing varying antimicrobial effects on pathogenic microorganisms. E. coli and C. albicans displayed the maximum susceptibility, with zones of inhibition of 14.6 and 13.8mm at 3-mM concentration, respectively, while B. cereus had the lowest zone of inhibition (10.6mm) at 3-mM OSC-AgN03 concentration. In conclusion, AgNPs synthesized from Oscillatoria princeps inhibit biofilm formation, suggesting that AgNPs may be a promising candidate for the prevention and treatment of biofilm-associated infections caused by bacteria and yeasts.

Characterization and Biological Activities of Silver Nanoparticles Synthesized using Grewia tiliifolia Vahl Leaf Extract

Background: An eco-friendly approach for the synthesis of noble metal nanoparticles employing various plant extracts has become of great interest in the field of nanotechnology. In the present study, the efficacy of Grewia tiliifolia leaf extract in reducing 1mM silver nitrate to silver nanoparticles(AgNPs) has been reported for the first time and also we investigated the anticancer, antituberculosis and antioxidant activity. Methods: Characterization of biosynthesized AgNPs using G. tiliifolia leaf extract was evaluated by Uv-Vis, FTIR, XRD, DLS and TEM with SAED. Efficacy of biosynthesized AgNPs using G. tiliifolia leaf extract was tested for cytotoxicity against A549 Lung cancer cell lines by MTT Assay and also against the infectious agent Mycobacterium tuberculosis using MABA Assay. Further antioxidant activity was evaluated by DPPH radical scavaging assay. Results: The biosynthesis of AgNPs was evident by color change of reaction mixture from dark yellow to reddish-brown. Biofabricated AgNPs was further confirmed by characteristic surface plasmon absorption peak at 409nm by UV-vis analysis. FTIR data reveals the presence of phytochemicals involved in bioreduction and biocapping of AgNPs, XRD analysis depicted crystallographic nature of AgNPs. Further, size, charge, and polydispersity nature were studied using DLS (40.2nm with polydispersity index 0.361) and Zeta potential (-35.8mV). The morphology of AgNPs was determined by TEM analysis with size ranging from 11-34nm. The plant derived AgNPs exhibited a cytotoxic effect on the Lung cancer cell line with IC50 value of 23.45µg/ml and also found to be effective against M. tuberculosis with a MIC of 6.25µg/ml in comparison to the leaf extract (MIC 50µg/ml). Antioxidant activity observed by AgNPs was moderate with IC50 value 49.60 µg/ml. Conclusion: The findings indicate that the AgNPs synthesized from leaf extract of G. tiliifolia are eco-friendly, cost-effective, non-toxic and can be the effective natural anticancer, antituberculosis agents and antioxidant agent.

Bioprospects of Endophytic Bacteria in Plant Growth Promotion and Ag-Nanoparticle Biosynthesis.

In this study, five endophytic bacterial strains, namely Rhizobium pusense (MS-1), Bacillus cereus MS-2, Bacillus flexus (MS-3), Methylophilus flavus (MS-4), and Pseudomonas aeruginosa (MS-5), were used to investigate their potential role in the enhancement of growth yields of two types of tomato varieties, viz. hybrid and local, and in the biosynthesis of silver nanoparticles (AgNPs). The inoculation of bacterial strains enhanced the root and shoot length, biomass, and leaf chlorophyll contents. The fruit weight of the tomato (kg/plant) was also higher in the bacteria inoculated plants of both hybrid and local varieties than in the control (untreated). A significant increase was recorded in the fruit yield (g/plant) in all the treatments, whereas Methylophilus flavus (MS-4) inoculated plants yielded nearly 2.5 times more fruit weight compared to the control in the hybrid variety and two times higher in the local variety. The response to M. flavus as a microbial inoculant was greater than to the other strains. Biosynthesis of Ag nanoparticles was also carried out using all five endophytic bacterial strains. The weakest producers of AgNPs were Rhizobium pusense (MS-1) and Methylophilus flavus (MS-4), while Bacillus cereus MS-2, Bacillus flexus (MS-3), and Pseudomonas aeruginosa (MS-5) were strong producers of AgNPs. Nanoparticles were further characterized using high-resolution scanning electron microscopy (HR-SEM), transmission electron microscopy (TEM), Fourier transform infrared (FTIR), UV-Vis spectrophotometry, and X-ray diffraction (XRD) analysis, and revealed cuboidal shaped AgNPs in the Bacillus cereus MS-2 strain. In addition, the biosynthesized AgNPs showed antibacterial activity against various pathogenic and endophytic bacterial strains.

A methanogenic protein facilitates the biosynthesis of the silver nanoparticles

Silver nanoparticles (AgNPs) have recently attracted worldwide consideration because of their extensive applications. Within the clean production trends, eco-friendly approaches have been provided as an alternative which require less energy consumptions and polluting chemicals. Herein, a purified protein (methyl-coenzyme M reductase D subunit, McrD) from methanogen as bio-reducing agent was used for biosynthesis of AgNPs and the critical factor is mainly related to the characteristics of the protein itself. The obtained optimum condition for synthesis in the mixture was 15 mM silver nitrate and 150 μg mL−1 McrD protein at 30 °C and pH 11 for 24 h incubation. Readily proteins displayed a rapid reduction of silver ion to elementary silver, yielding the spherical AgNPs at a nano-scale of 20 nm. In addition, this eco-friendly synthesized AgNPs possessed a broad-spectrum antimicrobial activity against bacteria and fungi. This work also envisages the possibility of predicting the biological properties of a protein on synthesizing the metal nanoparticles. Overall, this green and facile method is expected to the trend of biosynthesis of synthesizing AgNPs.

Green synthesis of silver nanoparticles using Cinnamomum tamala (Tejpata) leaf and their potential application to control multidrug resistant Pseudomonas aeruginosa isolated from hospital drainage water

Green Synthesis of Metal Nanoparticles is becoming a more common method for producing nanoparticles with a diameter of 1–100 nm that may be employed in a variety of medical applications. The antibacterial efficacy of silver nanoparticles (AgNPs) derived from Cinnamomum tamala (Tejpata) leaf extract against antibiotic-resistant Pseudomonas aeruginosa is investigated in this study. Green AgNP synthesis is safe, cost-effective, and ecologically friendly. The biosynthesized AgNPs were studied using UV-Visible spectroscopy, Fourier Transform Infrared Spectroscopy (FTIR), Dynamic Light Scattering (DLS), X-ray Diffraction (XRD), and Transmission Electron Microscopy (TEM). The AgNPs were virtually spherical, with an average size of 25–30 nm, according to TEM observations. Biochemical and molecular identification were used to isolate multidrug-resistant P. aeruginosa from the hospital's drainage water. The antibacterial potential of AgNPs against P. aeruginosa is determined using the agar diffusion method. Silver nanoparticles produced from Cinnamomum tamala (Tejpata) leaf extract were shown to be effective in inhibiting four strains of P. aeruginosa. According to the agar disc diffusion method, AgNPs had the largest inhibition zone of 17.67 ± 0.577 mm, while aqueous extract had 5.67 ± 0.5777 mm, indicating that AgNPs had antibacterial activity. This study on AgNPs might assist with managing multidrug resistant pathogenic bacteria and be a possible source of medicinal application due to its potential antibacterial effect.