Polyphenolic extracts from pomegranate and watermelon wastes as substrate to fabricate sustainable silver nanoparticles with larvicidal effect against Spodoptera littoralis

The agricultural wastes adversely affect the environment; however, they are rich in polyphenols; therefore, this study aimed to employ polyphenol-enriched waste extracts for silver nanoparticles synthesis, and study the larvicidal activity of silver nanoparticles fabricated by pomegranate and watermelon peels extracts (PPAgNPs and WPAgNPs) against all larval instars of Spodoptera littoralis. The polyphenol profile of pomegranate and watermelon peel extracts (PP and WP) and silver nanoparticles was detected by HPLC. The antioxidant activity was estimated by DPPH, and FARP assays and the antimicrobial activity was evaluated by disc assay. The Larvicidal activity of AgNPs against Egyptian leaf worm was performed by dipping technique. The obtained AgNPs were spherical with size ranged 15–85 nm and capped with proteins and polyphenols. The phenolic compounds in silver nanoparticles increased about extracts; therefore, they have the best performance in antioxidant/reducing activity, and inhibit the growth of tested bacteria and yeast. The PPAgNPs were the most effective against the first instar larvae instar (LC₅₀ = 68.32 µg/ml), followed by pomegranate extract with (LC₅₀ = 2852 µg/ml). The results indicated that obvious increase in polyphenols content in silver nanoparticles enhance their larvicidal effect and increasing mortality of 1^st larval of S. littoralis Egyptian leafworms causing additive effect and synergism. We recommend recycling phenolic enriched agricultural wastes in producing green silver nanoprticles to control cotton leafworm that causes economic loses to crops.     

Exopolysaccharide-mediated silver nanoparticles produced by <Emphasis Type="Italic">Lactobacillus brevis</Emphasis> NM101-1 as antibiotic adjuvant

A green, simple and effective approach was performed to synthesize potent silver nanoparticles using bacterial exopolysaccharide as both a reducing and stabilizing agent. The formation of nanoparticles was first screened by measuring the surface plasmon resonance peak around 400 nm using UV-vis spectroscopy. The morphology of the synthesized AgNPs was determined using TEM, which indicated that the AgNPs were spherical in shape and with an average size of 11–25 nm. The presence of elemental silver of the AgNPs was confirmed by EDX analysis. The possible functional groups of EPS responsible for the reduction and stabilization of AgNPs were evaluated using FTIR. The EPS reduced AgNPs showed excellent antibacterial, and antibiofilm activities against various human pathogenic bacteria. In addition, the efficiency of AgNPs with various broad-spectrum antibiotics against the tested strains was evaluated. It is evident that, the antibacterial and antibiofilm activities of the selected antibiotics were increased in the presence of AgNPs. The increase in activity was more pronounced for gram-negative bacteria Pseudomonas aeruginosa and E. coli. Interestingly, the combination of antibiotics with AgNPs has significantly increased the membrane protein leakage and ROS generation than antibiotics or AgNPs alone. This work supports that AgNPs can be used to enhance the activity of existing antibiotics against gram-negative and gram-positive bacteria for the treatment of infectious diseases.     

Green synthesis of silver nanoparticles with Dalbergia spinosa leaves and their applications in biological and catalytic activities

The phytosynthesis of silver nanoparticles (AgNPs) by Dalbergia spinosa leaves (DSL) in aqueous extract was investigated. AgNPs were characterized by UV–visible absorption spectroscopy (UV–vis), transmission electron microscopy (TEM) and Fourier transform infra red spectrophotometry (FTIR). The results showed that the increase in the initial extract concentration at room temperature increased the mean size and widened the size distribution of the AgNPs, leading to a red shift and broadening the surface plasmon resonance absorption (439 nm). The results showed that the reducing sugars and flavonoids were primarily responsible for the bioreduction of silver ions and that their reductive capability was promoted at 36 °C. TEM analysis showed that the AgNPs were nearly spherical in shape with an average size of 18 ± 4 nm. When evaluated for in vitro antioxidant activity by DPPH, NO, hydrogen peroxide radicals, reducing power and CUPRAC assay methods in addition to anti-inflammatory activity by HBRC method, the silver nanoparticles exhibited considerably enhanced antioxidant and anti-inflammatory activity at the test doses when compared with that of the standards and the plant extract. Finally, the antibacterial activity of the AgNPs against two Gram-positive bacteria and two Gram-negative bacteria showed moderate antibacterial activity when compared with the standard and the plant extract. The synthesized silver nanoparticles were also effective in the catalytic reduction of 4-nitrophenol (4-NP) into 4-aminophenol (4-AP).     

Exploring the Therapeutic Properties of Alga-Based Silver Nanoparticles: Anticancer,Antibacterial, and Free Radical Scavenging Capabilities

The current study was designed to evaluate the antioxidant, anticancer and antimicrobial activities of silver nanoparticles (AgNPs) biosynthesized by Spirulina platensis extract. The biosynthesized silver nanoparticles were characterized using Fourier transform infrared (FT-IR) analysis, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD) analysis. The antioxidant activity of the biosynthesized AgNPs were determined via DPPH radical scavenging assay while its anticancer activity was determined using the MTT assay. The antimicrobial activity of the biosynthesized AgNPs were analyzed by disc diffusion method. Spirulina platensis acts as a reducing and capping agent. The efficacy of silver nanoparticles (AgNPs) in inhibiting the growth of Gram-negative bacteria, specifically Acetobacter, Klebsiella, Proteus vulgaris, and Pseudomonas aeruginosa, was assessed by the utilisation of the diffusion method. The study aimed to evaluate the efficacy of biosynthesized silver nanoparticles (AgNPs) against many strains of Pseudomonas aeruginosa bacteria. The findings of the study revealed that when administered in doses of 50 μl, 75 μl, and 100 μl, the largest observed zone of inhibition corresponded to measurements of 10.5 mm, 14 mm, and 16 mm, respectively. A zone of inhibition with dimensions of 8 mm, 10.5 mm, and 12 mm was detected during testing against Acetobacter at concentrations of 50 μl, 75 μl, and 100 μl, respectively. The findings also indicate that there is a positive correlation between the concentration of AgNP and the DPPH scavenging ability of silver nanoparticles. The percentage of inhibition observed at concentrations of 500 μg/ml, 400 μg/ml, 300 μg/ml, 200 μg/ml, and 100 μg/ml were recorded as 80±1.98, 61±1.98, 52±1.5, 42±1.99, and 36±1.97, respectively. In addition, it was observed that the silver nanoparticles exhibited the greatest antioxidant activity at a concentration of 500 g/ml, with a measured value of 80.89±1.99. The IC-50 values, representing the inhibitory concentration required to achieve 50 % inhibition, were found to be 8.16, 19.15, 30.14, 41.13, and 63.11 at inhibition levels of 36±1.97, 42±1.99, 52±1.5, 61±1.98, and 80±1.98, respectively.     

Silver nanoparticles from Prosopis glandulosa and their potential application as biocontrol of Acinetobacter calcoaceticus and Bacillus cereus

In the present study the characterization and properties of silver nanoparticles from Prosopis glandulosa leaf extract (AgNPs) were investigated using UV–Vis spectroscopic techniques, energy dispersive X-ray spectrometers (EDS), zeta potential and dynamic light scattering. The UV–Vis spectroscopic analysis showed the absorbance peaked at 487 nm, which indicated the synthesis of silver nanoparticles. The experimental results showed silver nanoparticles had Z-average diameter of 421 nm with higher stability (?200 mV). The EDS analysis also exhibited presentation of silver element. Additionally, the different concentrations of AgNPs (25, 50, 75 and 100 mg/mL) showed antibacterial activity against Acinetobacter calcoaceticus and Bacillus cereus. Finally, AgNPs from leaf extracts of P. glandulosa may be used as an agent of biocontrol of microorganism of importance medical. However, further studies will be needed to fully understand the antimicrobial activity of silver nanoparticles obtain from P. glandulosa.     

Antioxidant,cytotoxic and antibacterial potentials of biosynthesized silver nanoparticles using bee’s honey from two different floral sources in Saudi Arabia

Nowadays, the innovative study of silver nanoparticles (AgNPs) is excessive since they have incredible biomedical applications. The current study aimed to find out the potential of honey from two different floral sources (Ziziphus spina-christi and Acacia gerrardii) as biogenic mediators to synthesize AgNPs and to evaluate their antioxidant, cytotoxic and antimicrobial abilities. Biogenic AgNPs were studied for particle characterizations and the expected biomolecules helped in the reduction process of silver (Ag) ions to AgNPs. Results demonstrated different sizes (50–98 nm) and potentials −42 and −40 for AgNPs prepared using different biological materials, therefore different 1,1-Diphenyl-2-picrylhydrazyl (DPPH) scavenging free radicals were observed. Cytotoxic effect in a dose-dependent manner was detected against HepG2 ca cells for biogenic AgNPs resulted from cell apoptosis that detected by caspase 3/7 activation and AO/EB staining in the treated cells compared to their corresponding controls. Furthermore, biogenic AgNPs suppressed the growth of Methicillin-resistant bacteria Staphylococcus aureus (Gram-positive) besides Escherichia coli and Peseudomonas aeruginosa (Gram-negative). The IC₅₀ of AgNPs was between 15.8 and 14.1 μg/mL and the antibacterial capability was between 22.8 ± 1.2 and 17.0 ± 0.1 mm. Bacterial membrane disturbance was evident in the current study when treated bacteria were studied by field emission scanning electron microscopy (FE-SEM) in relation to untreated controls. Overall, the present findings indicated the possibility of simple green synthesis of AgNPs using bee’s honey, which are effective agents in some biomedical applications. Detailed future work is needed to further validate the results.     

Phytotoxicity of green synthesized silver nanoparticles on Camelina sativa L

Due to the increased production and release of silver nanoparticles (AgNPs) in the environment, the concerns about the possibility of toxicity and oxidative damage to plant ecosystems should be considered. In the present study, the effects of different concentrations of AgNPs (0, 0.5, 1, 2, 3 and 4 g/L) synthesized using the extract of camelina (Camelina sativa) leaves on the growth and the biochemical traits of camelina seedlings were investigated. The results showed that AgNPs significantly increased Ag accumulation in the roots and shoots which decreased the growth and photosynthetic pigments of camelina seedlings. The highest decrease in the height and total dry weight was observed by 53.1 and 61.8% under 4 g/L AgNPs, respectively over control plants. AgNPs application over 2 g/L enhanced the accumulation of proline, malondialdehyde, hydrogen peroxide and methylglyoxal, and up-regulated the activity of antioxidant enzymes (superoxide dismutase, catalase, ascorbate peroxidase and glutathione reductase) and glyoxalase (glyoxalase I and II) system which indicates oxidative stress induction in camelina seedlings. Moreover, AgNPs reduced ASA and GSH contents and increased DHA and GSSG contents, hence disrupting the redox balance. These results showed that AgNPs at 4 g/L had the most toxic effects on the camelina growth. Therefore, increasing oxidative stress markers and the activity of antioxidant enzymes and enzymes involved in glyoxalase system indicated the oxidative stress induced by AgNPs treatments over 2 g/L as well as the induction of antioxidant defense systems to combat AgNPs-induced oxidative stress.     

Biosynthesis, characterization and antibacterial activity of silver nanoparticles by aqueous Annona squamosa L. leaf extract at room temperature

Silver nanoparticles (AgNPs) have gained great interest in nanotechnology, biotechnology and medicine. The green synthesis of nanoparticles has received an increasing attention because of it’s maximize efficiency and minimize health and environmental hazards as compared to other conventional chemical synthesis. In this study, we reported biosynthesis of AgNPs by aqueous Annona squamosa L. leaf extract and its characterization by UV-visible spectroscopy (UV–vis), Field emission gun scanning electron microscopy (FEG-SEM), X-ray energy dispersive spectroscopy (EDX), Transmission electron microscopy (TEM), Selected-area electron diffraction (SAED) and Fourier transform infra-red spectroscopy (FTIR). The results indicated that AgNPs formed were spherical in shape with size ranging from 14 to 40 nm with an average diameter 28.47 nm. Furthermore, it was observed that the AgNPs exhibited an antibacterial activity against different Gram positive and Gram negative microorganisms. Our report confirmed that the ALE is a very good eco-friendly and nontoxic bioreductant for the synthesis of AgNPs and opens up further opportunities for fabrication of antibacterial drugs, medical devices and wound dressings.     

Antibiofilm and antimicrobial activities of green synthesized silver nanoparticles using marine red algae Gelidium corneum

In our study, green synthesis of silver nanoparticles was carried out using a red algae Gelidium corneum extract as reducing agent. The obtained silver nanoparticles were characterized by UV–vis, TEM, XRD, FTIR and ICP-MS measurements. FTIR measurements indicated the possible functional groups responsible for the stabilization and reduction of nanoparticles, while XRD analysis results explained the crystalline structure of the particles with centric cubic geometry. TEM micrographs showed that the size of the nanoparticles was between 20–50 nm. According to the broth microdilution test results, AgNPs showed a high antimicrobial activity with very low MIC values (0.51 μg/ml for Candida albicans yeast and 0.26 μg/ml for Escherichia coli bacteria). The different ultrastructural effects of silver nanoparticles on yeast and bacterial cells were observed by TEM. Antibiofilm efficacy studies were also examined in two stages as prebiofilm and postbiofilm effect. In prebiofilm effect studies, AgNPs (0.51 μg/ ml) exhibited 81% reducing effect on biofilm formation. The highest reduction rate in postbiofilm studies was 73.5% and this was achieved with 2.04 μg/ml AgNPs. Our data support that the silver nanoparticles obtained by this environmentally friendly process have potential to be used for industrial and therapeutic purposes.     

Fruit extract capped colloidal silver nanoparticles and their application in reduction of methylene blue dye

Green synthesis of silver nanoparticles (AgNPs) has become a promising environmentally benign synthetic route in nanoscience and nanotechnology during recent years. In the present work, we have developed an environment-friendly and low-cost method for synthesis of silver nanoparticles from silver nitrate using aqueous fruit extract of Dillenia indica. The as-synthesized nanoparticles were characterized by UV-Vis spectrophotometer, transmission electron microscopy (TEM) and X-ray diffraction (XRD). FTIR study was performed to know the interaction of bio-molecules present in the fruit extract with AgNPs. The catalytic application of the as-synthesized AgNPs was demonstrated against degradation of methylene blue (MB) in aqueous system. The absorption spectra of colloidal suspension of AgNPs showed characteristic surface plasmon resonance (SPR) band centred at a wavelength of 416?nm. TEM image showed that the AgNPs were almost spherical in shape having an average diameter of 10.78?±?.48?nm. XRD pattern and selected area electron diffraction (SAED) pattern with bright spots signify the crystalline nature of nanoparticles. The fruit extract-capped AgNPs was highly stable and have showed the effective catalytic activity in reduction of MB dye.     

How the surface properties affect the nanocytotoxicity of silver? Study of the influence of three types of nanosilver on two wheat varieties

The influence of silver nanoparticles on calli cells of stress tolerant—Parabola and stress sensitive—Raweta wheat genotypes (Triticum aestivum L.) was studied. Three types of silver nanoparticles (AgNPs) were tested: cystamine-stabilized (positively charged), unmodified, synthesized using sodium borohydride and citrate-stabilized AgNPs, both negatively charged. Physico-chemical properties of silver nanoparticles were investigated by: UV–Vis spectroscopy, dynamic light scattering used for electrophoretic mobility and hydrodynamic diameter determination and transmission electron microscopy. The evaluation of cytotoxicity was estimated basing on lipid peroxidation, proline content and antioxidant enzymes activity. For sensitive variety every type of nanoparticles induced stress (proline increase) in cells, but positively charged nanoparticles were most cytotoxic. Treatment of stress tolerant Parabola by AgNPs caused the increase in SOD activity, suggesting the occurrence of oxidative stress in cells, confirmed by the increase of membrane lipid peroxidation. Negatively charged AgNPs were significantly more cytotoxic to the calli cells of sensitive variety in comparison to tolerant one.     

Role of reactive oxygen species in the antibacterial mechanism of silver nanoparticles on Escherichia coli O157:H7

In this study, the conditions and mechanism of antibacterial activity of hydrophilic polymer coated silver nanoparticles (AgNPs) against E. coli O157:H7 (CMCC44828) as model pathogen was studied. The AgNPs were coated with amphiphilic polymer that introduced carboxyl groups on the surface to make it water-soluble. The AgNPs were exposed to various treatment conditions of pH and temperature before these were combined with the E. coli. The mechanism of the antibacterial activity was studied through the formation of reactive oxygen species (ROS) that was later suppressed with antioxidant to establish correlation with the AgNPs antimicrobial activity. Studies were carried out at both anaerobic and aerobic conditions. The results indicated that 5 mg/L AgNPs inhibited ~50% of the growth of 10⁶ colony forming units per milliliter (cfu/mL) E. coli cells in liquid Luria–Bertani (LB) medium. This dose-dependent antimicrobial activity was higher at increased temperature (37°C) but was lower when the AgNPs were treated with acid at pH 2 before exposure to the bacteria. It was also established that the conditions of higher antimicrobial effect generated more ROS that was dependent on the presence of oxygen. The antibacterial activity was suppressed in the presence of an antioxidant.     

Ultrastructural Analysis of Candida albicans When Exposed to Silver Nanoparticles

Candida albicans is the most common fungal pathogen in humans, and recently some studies have reported the antifungal activity of silver nanoparticles (AgNPs) against some Candida species. However, ultrastructural analyses on the interaction of AgNPs with these microorganisms have not been reported. In this work we evaluated the effect of AgNPs on C. albicans, and the minimum inhibitory concentration (MIC) was found to have a fungicidal effect. The IC₅₀ was also determined, and the use of AgNPs with fluconazole (FLC), a fungistatic drug, reduced cell proliferation. In order to understand how AgNPs interact with living cells, the ultrastructural distribution of AgNPs in this fungus was determined. Transmission electron microscopy (TEM) analysis revealed a high accumulation of AgNPs outside the cells but also smaller nanoparticles (NPs) localized throughout the cytoplasm. Energy dispersive spectroscopy (EDS) analysis confirmed the presence of intracellular silver. From our results it is assumed that AgNPs used in this study do not penetrate the cell, but instead release silver ions that infiltrate into the cell leading to the formation of NPs through reduction by organic compounds present in the cell wall and cytoplasm.     

Effects of exposure of callus cells of two wheat varieties to silver nanoparticles and silver salt (AgNO<Subscript>3</Subscript>)

Metal nanoparticles significantly affect the physiological properties of plants, e.g., seed germination, growth and metabolism. In the present study, the toxic effects of silver nanoparticles (AgNPs) and silver ions were studied on callus cells of two varieties of wheat (Triticum aestivum L.): stress tolerant—Parabola; stress sensitive—Raweta. Stress induced by silver particles or ions (0, 20, 40, 60 ppm) was investigated using different parameters such as morphological characteristics, lipid peroxidation and mobilization of defense system which was determined by analyzing the activity of antioxidant enzymes, glutathione (GSH) and proline contents. Microscopic observations revealed deformation of cells after treatment by sol of higher silver concentrations. An increase in malondialdehyde content in both studied varieties was observed. Tested varieties showed an increased proline content in the silver-treated cells. There was no effect of silver on the superoxide dismutases activity, while the activity of catalase was significantly decreased. The changes in the activity of peroxidases in both varieties were opposite. The highest content of intracellular GSH was noticed at a concentration of 20 ppm of both AgNPs and silver ions. The presented results demonstrate a significant similarity of the effects caused by the studied stressors: silver nanoparticles and silver ions. The results characterized the mechanism of action of nanosilver on wheat callus: morphology disorder, damage to cell membranes, severe oxidative stress and in consequence intensification of production of non-enzymatic antioxidants.     

Synthesis of silver nanoparticles using haloarchaeal isolate Halococcus salifodinae BK3

Numerous bacteria, fungi, yeasts and viruses have been exploited for biosynthesis of highly structured metal sulfide and metallic nanoparticles. Haloarchaea (salt-loving archaea) of the third domain of life Archaea, on the other hand have not yet been explored for nanoparticle synthesis. In this study, we report the intracellular synthesis of stable, mostly spherical silver nanoparticles (AgNPs) by the haloarchaeal isolate Halococcus salifodinae BK₃. The culture on adaptation to silver nitrate exhibited growth kinetics similar to that of the control. NADH-dependent nitrate reductase was involved in silver tolerance, reduction, synthesis of AgNPs, and exhibited metal-dependent increase in enzyme activity. The AgNPs preparation was characterized using UV–visible spectroscopy, XRD, TEM and EDAX. The XRD analysis of the nanoparticles showed the characteristic Bragg peaks of face-centered cubic silver with crystallite domain size of 22 and 12 nm for AgNPs synthesized in NTYE and halophilic nitrate broth (HNB), respectively. The average particle size obtained from TEM analysis was 50.3 and 12 nm for AgNPs synthesized in NTYE and HNB, respectively. This is the first report on the synthesis of silver nanoparticles by haloarchaea.     

The toxic influence of silver and titanium dioxide nanoparticles on cultured ovarian granulosa cells

The application of metal nanoparticles in modern society is growing, but there is insufficient data concerning their influence on reproductive processes and comparison of their biological activity. The present experiments aimed to compare the effects of silver and titanium dioxide nanoparticles (AgNPs and TiO2NPs) on ovarian granulosa cell functions. AgNPs and TiO2NPs were added to culture of porcine granulosa cells at doses 0, 0.01, 0.1, 1 or 10 μg/mL. The mRNAs for proliferating cell nuclear antigen (PCNA), cyclin B1, bax and caspase 3 were quantified by RT-PCR; release of progesterone was analyzed by ELISA. It was shown that both AgNPs and TiO2NPs significantly reduced all the measured parameters. ED₅₀ of the inhibitory influence of AgNPs on the main ovarian cell parameters was higher than ED₅₀ of TiO2NPs. The ability of AgNPs and TiO2NPs to suppress ovarian granulosa cell functions should be taken into account by their application.     

Quasi‐spherical silver nanoparticles with high dispersity and uniform sizes: preparation,characterization and bioactivity in their interaction with bovine serum albumin

A stepwise seeded growth route for the preparation of silver nanoparticles (AgNPs) is reported. In the process, silver nitrate was used as a precursor, with sodium borohydride as a reducing agent and trisodium citrate as both a reductant and stabilizer. The AgNPs were characterized using several methods, including UV–vis spectroscopy, X‐ray diffraction and transmission electron microscopy. The prepared AgNPs were quasi‐spherical and crystalline, with an average diameter of 21 nm. Interactions between the AgNPs and bovine serum albumin (BSA) were investigated using UV–vis, fluorescence spectroscopy and synchronous fluorescence spectroscopy (SFS). It was proved that the quenching mechanism is a static process. The binding constants and number of binding sites were calculated. The thermodynamic parameters implied that the binding process was spontaneous and the main driving force of the interaction was electrostatic. The results of the SFS indicated that the conformational change of BSA was induced by AgNPs. Copyright © 2016 John Wiley & Sons, Ltd.     

Growth of Ag-nanoparticles in an aqueous solution and their antimicrobial activities against Gram positive,Gram negative bacterial strains and Candida fungus

Silver nanoparticles (AgNPs) were synthesized using Ocimum sanctum (Tulsi) leaves aqueous extract as reducing as well as a capping agent in absence and presence of cetyltrimethylammonium bromide (CTAB). The resulting nanomaterials were characterized by UV–visible spectrophotometer, and transmission electron microscope. The UV–Vis spectroscopy revealed the formation of AgNPs at 400–450 nm. TEM photographs indicate that the truncated triangular silver nanoplates and/or spherical morphology of the AgNPs with an average diameter of 25 nm have been distorted markedly in presence of CTAB. The AgNPs were almost mono disperse in nature. Antimicrobial activities of AgNPs were determined by using two bacteria (Gram positive Staphylococcus aureus MTCC-3160), Gram negative Escherichia coli MTCC-450) and one species of Candida fungus (Candida albicans ATCC 90030) with Kirby-Bauer or disc diffusion method. The zone of inhibition seems extremely good showing a relatively large zone of inhibition in both Staphylococcus aureus, Escherichia coli, and Candida albicans strains.     

Avicennia marina engineered nanoparticles induce apoptosis in adenocarcinoma lung cancer cell line through p53 mediated signaling pathways

The biogenic engineered silver nanoparticles (AgNPs) were synthesized using aqueous extract of marine mangrove Avicennia marina leaves and its anticancer activity was checked in lung cancer cell line. Initially, the UV–vis spectra exhibited the characteristics SPR absorption peak for AgNPs at 425 nm and further characterized using TEM, SAED, XRD and FT-IR analysis. The TEM pictures displayed the spherical crystalline and monodispersed nature of AgNPs and the size range observed between 25–30 nm. The SAED showed the AgNPs are face-centered cubic pattern which is further confirmed with XRD analysis. The FTIR spectral analysis exposed the presence of necessary biomolecules for the reduction and stabilization of silver ions. Synthesized AgNPs showed dose-dependent cytotoxic activity in A549 cell line. The fluorescence studies showed that AgNPs induces apoptosis by increasing the generation of ROS in mitochondria and cleaving the mitochondrial membrane of A549 cells. Further, the molecular studies were conducted using RT-PCR and western blotting analysis and the results confirmed that the AgNPs induce apoptosis through both p53-dependent and -independent caspase intermediated signaling pathway. Together, the present study concludes that the bioengineered AgNPs can act as a potential therapeutic agent against lung cancer.     

Morphology and antibacterial activity of carbohydrate-stabilized silver nanoparticles

Silver nanoparticles were prepared by a simple hydrothermal route and chemical reduction using carbohydrates (sucrose, soluble and waxy corn starch) as reducing as well as stabilizing agents. The crystallite size of these nanoparticles was evaluated from X-ray diffraction (XRD) and transmission electron microscopy (TEM) and was found to be 25 nm. The effect of carbohydrates on the morphology of the silver nanocomposites was studied using scanning EM (SEM). The nanocomposites exhibited interesting inhibitory as well as bactericidal activity against both Gram positive and Gram negative bacteria. Incorporation of silver also increased the thermal stability of the carbohydrates.