Biosynthesized Ag Nanoparticles Research Articles

Hybrid Materials Obtained by Immobilization of Biosynthesized Ag Nanoparticles with Antioxidant and Antimicrobial Activity.

Ag nanoparticles (AgNPs) were biosynthesized using sage (Salvia officinalis L.) extract. The obtained nanoparticles were supported on SBA-15 mesoporous silica (S), before and after immobilization of 10% TiO2 (Degussa-P25, STp; commercial rutile, STr; and silica synthesized from Ti butoxide, STb). The formation of AgNPs was confirmed by X-ray diffraction. The plasmon resonance effect, evidenced by UV-Vis spectra, was preserved after immobilization only for the sample supported on STb. The immobilization and dispersion properties of AgNPs on supports were evidenced by TEM microscopy, energy-dispersive X-rays, dynamic light scattering, photoluminescence and FT-IR spectroscopy. The antioxidant activity of the supported samples significantly exceeded that of the sage extract or AgNPs. Antimicrobial tests were carried out, in conditions of darkness and white light, on Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli and Candida albicans. Higher antimicrobial activity was evident for SAg and STbAg samples. White light increased antibacterial activity in the case of Escherichia coli (E. coli) and Pseudomonas aeruginosa (P. aeruginosa). In the first case, antibacterial activity increased for both supported and unsupported AgNPs, while in the second one, the activity increased only for SAg and STbAg samples. The proposed antibacterial mechanism shows the effect of AgNPs and Ag+ ions on bacteria in dark and light conditions.

Eco-friendly Biosynthesis of Ag-NPs by Streptomyces griseus With Anti- Candida albicans and Antitumor Activity.

The most significant sexually transmissible fungal disease, semen candidiasis, is caused by Candida albicans and impacts male reproductive potential. Actinomycetes are a group of microorganisms that could be isolated from various habitats and used for the biosynthesis of various nanoparticles with biomedical applications. Testing antifungal activity of biosynthesized Ag nanoparticles versus isolated C. albicans from semen as well as its anticancer activity versus the Caco-2 cell line. Screening 17 isolated actinomycetes for the biosynthesis of Ag nanoparticle biosynthesis. Characterization of biosynthesized nanoparticles, testing its anti-Candida albicans, and antitumor activity. Streptomyces griseus was the isolate that identified silver nanoparticles using UV, FTIR, XRD and TEM. Biosynthesized nanoparticles have promising anti-Candida albicans with MIC (125 ± 0.8) µg/ml and accelerate apoptotic rate versus Caco-2 cells (IC50 = 7.30 ± 0.54 µg/ml) with minimal toxicity (CC50 = 142.74 ± 4.71 µg/ml) versus Vero cells. Certain actinomycetes could be used for the biosynthesis of nanoparticles with successive antifungal and anticancer activity to be verified by in vivo studies.

Comparative physiological and anatomical responses of Tagetes erecta L. and Zinnia elegans Jacq. seedlings to AgNO3 and ZnSO4 metals and their nanoparticles

Heavy metals (HMs) pose a significant ecological risk due to their enduring presence in the ecosystem. They become more prevalent as a result of urbanization and industrialization, disrupting critical functions of plant life such as photosynthesis, seedling growth, and germination. Understanding the impact of HMs and nanoparticle exposure on plants is crucial for developing effective strategies to mitigate their potential hazards. Therefore, an effort was made to elucidate the impact of biosynthesized Ag NPs (nanoparticles) and ZnO NPs versus their precursor metal salts, AgNO3 and ZnSO4, respectively on two Asteraceous plants, Mexican marigold (Tagetes erecta L.) and Zinnia (Zinnia elegans Jacq.) in hydroponic solution by monitoring the changes in photosynthetic pigments and their associated photochemistry of photosystem II along with the anatomical attributes. In the present study, two concentrations (50 μM and 100 μM) for each treatments viz., AgNO3, Ag NPs, ZnSO4 and ZnO NPs were given to the seedlings. Metal salts were found to be more toxic than their nanoparticles, and this was manifested in terms of reduction in photosynthetic pigments, especially chlorophylla content (by 32% in marigold and 27% in Zinnia upon exposure to 100 µM of AgNO3, respectively) in both test seedlings. Reduction in chlorophyll fluorescence parameters was also found under metal as well as nanoparticle toxicity. In contrast, energy flux parameters such as absorption of photon per active reaction centre (ABS/RC), trapped energy flux per active reaction centre (TR0/RC), electron transport flux per active reaction centre (ET0/RC) and energy dissipation flux per active reaction centre (DI0/RC) increased significantly to cope with stress toxicity. Similarly, metals and nanoparticles also distorted the anatomy of the root and leaf, and the effect was more intense under AgNO3 treatment than with ZnSO4 in Zinnia. In conclusion, Zinnia seedlings were more resilient towards all the tested conditions, which might be attributed to their adaptability to various environmental factors, indicating their potential for thriving in diverse climates.

Neuroprotective properties of plant extract green-formulated silver nanoparticles on the contusive model of spinal cord injury in rats

Silver nanoparticles (Ag NPs) are highly sought-after metal nanoparticles globally due to their distinctive electronic and optical characteristics, as well as their biological properties. These attributes stem from the synchronized movements of conduction electrons, referred to as surface plasmon resonance. Currently, numerous bio-medical characteristics of biosynthesized Ag nanoparticles have been thoroughly documented, including their anti-inflammatory, antioxidant, anticancer, and antimicrobial properties. Nevertheless, there have been no reports regarding the neuroprotective efficacy of these nanoparticles against cytotoxic agents. It appears that the defensive capabilities of the NPs formulated by green methods have been disregarded thus far. We recently did research to assess the neuroprotective effects of a combination of Tribulus terrestris and green-mediated silver nanoparticles on a contusive spinal cord injury model in animals. The silver nanoparticles underwent comprehensive characterization through UV–Vis, FE-SEM, FT-IR, and TEM analyses. In the in vivo phase of the research, a total of forty rats were categorized into three groups: untreated, normal, and silver nanoparticles (50 µg/kg) groups. The post-injury lesions were analyzed using H&E staining. To evaluate the restoration of neural conduction, somatosensory evoked potential testing was conducted. The presence of astrogliosis was determined by evaluating the expression of GFAP. The rats' behavioral outcomes were assessed using the BBB score every week. The utilization of silver nanoparticles demonstrated neuroprotective properties and resulted in enhancements in spinal cord injury. The results of the sensory assessments indicated a notable rise in the Basso, Beattie, and Bresnahan scales, along with a marked decline in delayed reactions, among the subjects who received treatment with silver nanoparticles. The most substantial decrease in GFAP levels was noted in the group that was administered silver nanoparticles. Furthermore, there was a substantial decrease in the size of the cavity regions, while the quantity of ventral motor neurons experienced a significant rise within the silver nanoparticles group. The electromyography (EMG) results demonstrated a remarkable enhancement in the hindlimbs of the subjects who received treatment with silver nanoparticles (50 µg/kg).

Improving the optical, thermal, mechanical, electrical properties and antibacterial activity of PVA-chitosan by biosynthesized Ag nanoparticles: Eco-friendly nanocomposites for food packaging applications

In this study, nanocomposite films were produced by blending polyvinyl alcohol (PVA) and chitosan (Cs) polymers with 70 % PVA and 30 % Cs, incorporating silver nanoparticles (Ag NPs) via a solution-casting method. The research aims to investigate the impact of the biosynthesized Ag NPs by Chenopodium murale leaf extract on optical, morphological, mechanical, thermal, electrical, and antibacterial properties. XRD analysis showed a decrease in crystallinity degree with Ag NPs addition. TEM revealed Ag NPs in cubic and spherical shapes with an average size of 23.4 nm. SEM and AFM indicated surface morphology changes. FT-IR spectra showed interaction between Ag ions and the blend. The energy gap decreased with increasing Ag NPs concentration. TGA exhibited enhanced thermal stability. Mechanical properties improved significantly. AC electrical conductivity and dielectric parameters were studied. Antibacterial activity against Gram-positive and Gram-negative bacteria was observed. Overall, PVA/Cs-Ag NPs films show promise for food packaging and optoelectronic applications.

Boosting the photocatalytic activity of g-C3N4 via loading bio-synthesized Ag0 nanoparticles and imidazole modification for the degradation and mineralization of fluconazole.

The emergence of fluorinated organic compounds in the pharmaceutical, agrochemical, and textile industries has led to a potential increase in the environmental issues and health problems. Herein, a modified heterojunction of bio-synthesized Ag nanoparticles (Ag0 NPs) immobilized on imidazole-modified graphite carbon nitride (Im/g-C3N4) as a suitable support (Ag0/Im/g-C3N4) was hydrothermally synthesized and studied for the photocatalytic removal of the most widely used antifungal organo-fluorine compound-fluconazole (FCZ). The optical properties were thoroughly investigated in the present study, and it was observed that the proposed modification to g-C3N4 has led to the shifting of conduction and valance band edge position (for g-C3N4, -0.73 and 1.54 eV and for ICA, -1.14 and 1.28 eV), narrowing of band gap energies, i.e., 2.01 eV, and reduced charge recombination rate. The external and internal surface morphologies were scrutinized through FE-SEM and HR-TEM analyses. Functionalities and potential crystallinity were investigated using FTIR and XRD techniques. The elemental state and composition of the composite were analyzed via XPS. The obtained results substantiate the intended modifications in the ICA composite. The photocatalyst Ag0/Im/g-C3N4 (ICA) was able to degrade 95.74% of FCZ with a high degradation rate (k1) of 0.0289 min-1 within 2-h of the solar illumination experiment. The overall degradation process was observed to be governed by a pseudo-first-order kinetic model. Detailed parameters such as effects of ions, pH (optimized pH 4, highest degradation rate k1 =0.039 min-1), dissolved organic matter (DOM), and optimization of catalysts dosage were studied. The major reactive oxygen species (ROS) was identified as super-oxide radicals (O2●-). The HR-MS and COD-TOC analysis were used to evaluate the degradation and mineralization of FCZ forced by ICA catalysts. The ICA catalyst was found to be stable and reusable for up to five cycles suggesting towards its potential towards the mitigation of environmental pollutants.

Preparation of bio-synthesized Ag nanoparticles and assessment of their antidiabetic and antioxidant potential against STZ-induced diabetic albino rats

Bio-synthesized silver nanoparticles (AgNPs) were successfully obtained using the leaf extract from Ventilago maderaspatana. Extensive analysis was conducted to evaluate the physical and chemical characteristics of the bioderived AgNPs. XRD analysis confirmed their cubic structure, and revealed a well-defined size distribution with average crystallite size of 11.7 nm. FE-SEM and TEM images visually supported the observed size range. The presence of plant-mediated phytochemicals on the surface of AgNPs was confirmed through DLS, FTIR, and TGA/DTA studies. To assess their antidiabetic potential, rats were induced with streptozotocin, resulting in elevated levels of biochemical parameters associated with diabetes. Conversely, serum insulin levels (2.50 ± 0.55) and glucokinase activity (64.50 ± 8.66) decreased. However, treatment with AgNPs demonstrated a dose-dependent reduction in blood glucose, total protein, albumin, and HbA1c levels, effectively restoring them to normal ranges. Moreover, the treatment significantly increased insulin levels (7.55 ± 0.63) and glucokinase activity (121.50 ± 4.60), indicating the antidiabetic potential of V. maderaspatana-mediated AgNPs. Notably, the exitance of phytochemicals, like flavonoids and phenols, on the surface of AgNPs facilitated their ability to neutralize reactive oxygen species (ROS) through electron donation. This property enhanced their overall antidiabetic efficiency.

Studies on phytochemical, mineral content, in vitro anti-urolithiatic and anti-diabetic activities of horse gram flour extracts and its biosynthesized Ag nanoparticles

The current study aims to examine the use of horse gram flour and its extracts as a low-cost source of mineral content with anti-urolithiatic, anti-diabetic properties and to compare the biological activities with its biosynthesized AgNPs. The secondary metabolites and the macro and micronutrients present in the selected herbal product, reinforces the utility of the horse gram as a promising herbal. Present investigation reveals that the biomass chosen for the study as a cheap natural source with valuable mineral content of calcium (43.06 mg/L), followed by potassium (13.78 mg/L) and sodium (6.94 mg/L). The grain's water extracts found to contain carbohydrate as dominating component with the value of (65.10 ± 0.95 mg g−1 equivalent). Whereas both water and ethanol extract contain TPC (phenol) viz; 60.13 ± 2.45 mg g−1, 68.24 ± 1.33 mg g−1, TTC (terpenoids)53.21 ± 1.4 mg g−1,51.27 ± 2.65 mg g−1, followed by TSC (sterol)as 45.58 ± 1.7 mg g−1, 57.27 ± 1.65 mg g−1 in moderate amounts respectively. The aqueous extract of Horse gram was used for the synthesis the AgNPs through a straightforward green approach and characterized by FESEM, TEM, zeta potential, X-ray diffraction, UV spectroscopy and particle size measurement. These studies demonstrate the production of AgNPs with an average particle size of 30 nm–60 nm. Investigation on anti-urolithiatic property with aqueous extract, (HGW), ethanol extract (HGE) and its biosynthesized Ag nanoparticles (HG-Ag) reveal that, among the three samples chosen, the biosynthesized Ag nanoparticles possess the best inhibiting activity. The disintegration of crystals in gel medium further validated the extracts and Ag nanoparticles crystal growth inhibitory activity, at concentrations of 2% for extracts and 200 μg/ml for AgNPs. Further, it is also found that the HG-Ag nanoparticle exhibit good anti-diabetic activity (75.36%) than the other two extracts (HGW Extract-67.18% & HGE Extract-44.29%). Thus, the seed flour extracts and its AgNps demonstrated to be a promising natural herbal product with potential mineral content, antidiabetic and anti-urolithiatic activities which could be a used as a value-added product in the dietary formulations.

Antibacterial Activity of the Green Synthesized Plasmonic Silver Nanoparticles with Crystalline Structure against Gram-Positive and Gram-Negative Bacteria.

Nanoparticles (NPs) have attracted considerable interest in numerous fields, including agriculture, medicine, the environment, and engineering. The use of green synthesis techniques that employ natural reducing agents to reduce metal ions and form NPs is of particular interest. This study investigates the use of green tea (GT) extract as a reducing agent for the synthesis of silver NPs (Ag NPs) with crystalline structure. Several analytical techniques, including UV-visible spectrophotometry, Fourier transform infrared (FTIR) spectroscopy, high-resolution transmission electron microscopy (HR-TEM), and X-ray diffraction (XRD), were used to characterize the synthesized Ag NPs. The results of UV-vis revealed that the biosynthesized Ag NPs exhibited an absorbance plasmonic resonance peak at 470 nm. According to FTIR analyses, the attachment of Ag NPs to polyphenolic compounds resulted in a decrease in intensity and band shifting. In addition, the XRD analysis confirmed the presence of sharp crystalline peaks associated with face-centered cubic Ag NPs. Moreover, HR-TEM revealed that the synthesized particles were spherical and 50 nm in size on average. The Ag NPs demonstrated promising antimicrobial activity against Gram-positive (GP) bacteria, Brevibacterium luteolum and Staphylococcus aureus, and Gram-negative (GN) bacteria, Pseudomonas aeruginosa and Escherichia coli, with a minimal inhibitory concentration (MIC) of 6.4 mg/mL for GN and 12.8 mg/mL for GP. Overall, these findings suggest that Ag NPs can be utilized as effective antimicrobial agents.

Biosynthesized Silver Nanoparticles Encapsulated in a Poly(vinyl alcohol) Matrix: Dielectric and Structural Properties

AbstractIn the present investigation, silver (Ag) nanoparticles were prepared employing green synthesis from the aqueous leaves extract of Cyperus rotundus (CR) plant at ambient temperature in less reaction time. A preliminary phytochemical analysis test was performed, and it has been revealed that the extract comprised bioactive components such as alkaloids, phenols, and terpenoids, among others. For average size, the morphology (spherical shape) and purity of the nanoparticles were characterized using scanning electron microscopy (SEM, 358 nm) with energy‐dispersive X‐ray (EDX), dynamic light scattering (27 nm), high‐resolution transmission electron microscopy (3.9 nm), and selected area electron diffraction (SAED) pattern methods. Without any extra peaks in the EDX spectrum, the produced Ag nanoparticles were confirmed to be pure. In addition, the solvent‐casting approach has been used to encapsulate a different weight fraction of biosynthesized Ag nanoparticles (CR−Ag−NPs) in a polyvinyl alcohol (PVA) matrix. By using UV‐visible, FTIR spectroscopy, and SEM, we were able to characterize the synthesized CR−Ag−NPs as well as their composite (PVA) films, and we were able to compare the results with those of pristine PVA. The effects of doping with CR−Ag−NPs on structural and morphological changes of PVA were studied. Impedance studies, including dielectric constant, dielectric loss, tangent loss, and AC conductivity, revealed that incorporating CR−Ag−NPs into the PVA matrix impacts the electrical properties of PVA. This study showed that the synthesized nanoparticles had a spherical shape with entangled biocomponents and were encapsulated within the PVA polymer matrix, indicating that CR−Ag−NPs can be used in various applications (wound healing).

Green Synthesis of Silver Nanoparticles Using Citrullus colocynthis Fruit Extract and the Eutectic-Based Ionic Liquid: Thin Film Application

Metallic nanoparticles (NPs) are of great importance owing to their unique distinctiveness and potential requests in numerous applications. Recently, silver (Ag) NPs, due to their unique and extraordinary properties, has been of interest to a large number of researchers. Overall, there are three essential approaches for manufacturing NPs, namely; chemical, physical and biological or green approaches. In the present study, Ag NPs have been synthesized using Citrullus colocynthis fruit extract and a eutectic-based ionic liquid, as a reducing, capping and stabilizing agent. Additionally, these mediums are one-pot, environmentally friendly and economic for synthesizing pure, stable, highly crystalline, thermally stable NPs. Then the biosynthesized Ag NPs were identified by means of diverse description methods to investigate their size, purity, stability, degree of crystallinity, structure, thermal and optical properties. Afterward, the biosynthesized Ag NPs, from both mediums, has been utilized for thin film preparation using the spin-coating method. The p-type silicon (100) wafer utilized as a substrate and the Ag NPs disseminated on the substrate homogeneously. The utilized characterization showed that the synthesized Ag NPs thin film possesses highly standard properties of thin film in which can be utilized for photovoltaic devices.

Optimization of biosynthesis of stabilized silver nanoparticles using bitter orange peel by-products and glycerol

Nowadays, the biosynthesis of metal nanoparticles (NPs) through eco-friendly, cost-effective, and sustainable methods has drawn considerable attention. In this study, the green synthesis of silver NPs using AgNO3 salt and the peel extract of bitter orange (Citrus aurantium) as a reducing agent was modeled and optimized by central composite design (CCD). Accordingly, the process parameters including pH (7–11), time (0–4 h), and the ratio of extract/salt solution (0:100–20:80 v/v) were considered to model the responses including the spectrophotometric wavelength of maximum absorbance (λmax) and the maximum absorbance value at λmax (Amax), which represented the size and concentration of Ag NPs, respectively. Additionally, the stabilizing effect of glycerol (ratio of glycerol to salt 0–10 g/g) on the optimum treatment was studied using spectrophotometric and SEM analyses. The results showed that the quadratic and linear models were acceptably fitted to the experimental responses of Amax and λmax, respectively. The optimization results demonstrated that the optimal reaction parameters to achieve the maximum Amax were pH = 10.92, time = 3.5 h and ratio of extract/salt = 17.94:82.06 (v/v). Furthermore, glycerol could favorably play a stabilizer role in the optimum biosynthesized Ag NPs during the reaction and 14 days of storage at room temperature. The ICP-OES and TEM analyses of the stabilized Ag NPs (with 2.5 g/g glycerol) showed the presence of Ag element as nanospheres with ∼20 nm in size. The Ag NPs had great antibacterial properties against Staphylococcus aureus and Escherichia coli. Therefore, the bitter orange peel extract and glycerol could be promisingly used as novel reducing and stabilizing agents, respectively, to synthesize nanosilver via an eco-friendly and economical green approach.

Colorimetric sensing of mercury ions using green synthesized silver nanoparticles from Trigonella foenum (Linnaeus)

Mercury ion sensing is an essential technology in water polluted countries especially India, China, south east Asian countries etc. This type of technology heavily relies on nano-sensing with silver nanoparticles. Colorimetric sensors are optical sensors that change color in response to an external input. A colorimetric sensor was developed to detect hazardous mercury ions in water. Silver nanoparticles will lose its UV–Vis absorption intensity when combined with mercury ions. Plant extract of Trigonella foenum (Linnaeus) was used to prepare silver nanoparticles in this study. Having a cubic form and an average crystallite size of 27.24 nm, the silver nanoparticles are widely distributed. Nanoparticles were found to be crystalline and has a cubic phase of geometry, as demonstrated by XRD and SEM investigation. Using biosynthesized Ag nanoparticles, we demonstrate very sensitive and specific colorimetric detection of the mercury ion (Hg2+).

3D imaging of single bacterial cells using surface-enhanced Raman spectroscopy with a multivariate curve resolution model

Imaging biomolecules within a single bacterial cell is crucial for understanding cellular genetic mechanisms. Herein, we exploited a surface-enhanced Raman spectroscopy (SERS) imaging strategy for single cell analysis. Cellular biosynthesized Ag nanoparticles (NPs) provided the necessary enhancement for SERS imaging. Multiple complementary techniques, including high-resolution transmission electron microscopy (HR-TEM), high-angle annular dark-field (HAADF)-scanning transmission electron microscopy (STEM), and energy-dispersive X-ray spectroscopy (EDX), were used to characterize the biogenic Ag NPs in cells. Three-dimensional SERS imaging maps displayed spectral information of biomolecules within the single cell. The multivariate curve resolution (MCR) model and principal component analysis (PCA) model were used to analyze the cellular SERS imaging maps. The MCR model, with a specific constraint of non-negativity, resulted in meaningful identification of biomolecules associated with Ag reduction. Focusing on the molecular level reveals that Pantoea sp. IMH utilizes several mechanisms to synthesize Ag NPs, including cytoplasm reduction by glucose or nicotinamide adenine dinucleotide (NADH)-dependent reductase, and extracellular reduction by an electron transfer chain containing quinone and cytochrome C. Our results shed new light on the Ag NP biosynthesis mechanism and single cell Raman analysis.

Biosynthesis of Silver Nanoparticles and Their Applications in Harvesting Sunlight for Solar Thermal Generation.

Silver (Ag) nanoparticles (NPs) have been synthesized through an easy, inexpensive, and ecofriendly method. Petroselinum crispum, parsley, leaf extract was utilized as a reducing, capping, and stabilizing agent, without using any hazardous chemical materials, for producing Ag NPs. The biosynthesized Ag NPs were characterized using different characterization techniques, namely UV-Vis, FT-IR spectroscopy, X-ray diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS), dynamic light scattering (DLS), zeta potential, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), transmission electron microscope (TEM), field emission scanning electron microscopy (FESEM), and energy-dispersive X-ray (EDX) analysis to investigate the optical, thermal, structural, morphological, and chemical properties of the plant extract and the biosynthesized Ag NPs. After that, the biosynthesized Ag NPs were utilized in harvesting sunlight for solar thermal generation. Surface plasmon resonance (SPR) for the green synthesized Ag NPs with the dark color were adjusted at nearly 450 nm. Once the Ag NPs are excited at the SPR, a large amount of heat is released, which causes a change in the local refractive index surrounding the Ag NPs. The released heat from the Ag NPs under the solar irradiation at the precise wavelength of plasmon resonance significantly increased the temperature of the aqueous medium. Different percentages of Ag NPs were dispersed in water and then exposed to the sunlight to monitor the temperature of the suspension. It was found that the temperature of the aqueous medium reached its highest point when 0.3 wt. % of Ag NPs was utilized. This investigation is rare and unique, and it shows that utilizing a small amount of the biosynthesized Ag NPs can increase the temperature of the aqueous medium remarkably.

Green synthesis of antimicrobial silver nanoparticles with Brassicaceae seeds

Herein, we demonstrate a facile and green route for the synthesis of silver nanoparticles (AgNPs) from silver nitrate and seed extracts of different vegetable seeds of Brassicaceae family. All the nanocomposites were fully characterized in the solid-state via various techniques such UV–vis spectrophotometer (UV–Vis); x-ray diffraction (XRD), High-resolution transmission electron microscopy (HR-TEM), energy-dispersive x-ray spectroscopy (EDS), and Fourier transform infrared (FTIR) spectrometry. The experimental parameters such as variation in seeds extract concentration, temperature, stirring time and pH were noted and optimum condition of concentration (20 ml), temperature (80 °C) and pH 8.5 was selected for the synthesis of NPs. Optical absorbance of AgNPs at ≈425 nm indicated the formation of metallic silver through surface plasmon resonance. The successful capping of biological macromolecules was confirmed by FTIR spectroscopy. XRD pattern depicted the formation of face-centered cubic silver nano-composite with average crystal size ranges from ≈14–20 nm. Bio-synthesized Ag nanoparticles showed enhanced antibacterial potential against gram-positive (B. safensis, B. subtilis, B. pumilis and S. aureus) and negative gram (E. coli and S.typhi) strains by disc diffusion method. Highest antimicrobial activity was given by sample S3 (17 mm) against B. pumilis whereas, sample S2 and S5 also showed significant bactericidal potential against B. pumilis that is 15 mm. While highest zone of inhibition for sample S1 and S4 is 14 mm.

Characterization and Evaluation of Multiple Biological Activities of Silver Nanoparticles Fabricated from Dragon Tongue Bean Outer Peel Extract.

BackgroundThe dragon tongue beans are a legume belonging to the Fabaceae family, are rich in protein, starch, fiber, and other micronutrients that have numerous health-promoting benefits. Its peel commonly the waste parts also contains lots of bioactive compounds.Materials and MethodsIn the current research, dragon tongue bean peels (DtbP) extract is tested for the existence of phytochemicals. Ag nanoparticles are biosynthesized using DtbP extract. The generated DtbP silver nanoparticle characterization was accomplished using UV-Vis spectral analysis, FTIR spectral analysis, SEM analysis, EDX analysis, XRD analysis, zeta potential, and DLS study. Furthermore, comparative assessment on multi-biological activities of the biosynthesized Ag nanoparticles was accomplished by employing cytotoxicity (inhibition against HepG2 cancer cells), antidiabetic (α-glucosidase inhibition assay), and antioxidant (free-radical scavenging) analysis.ResultsThe characterization result of the DtbP-AgNPs demonstrated that the AgNPs synthesized within 24 h. The AgNPs are nearly spherical. The biological effect assay of AgNPs displayed that DtbP-AgNPs is having significant cytotoxicity, antidiabetic, and moderate antioxidant effect. This study results as a whole report the biosynthesis of DtbP-AgNPs utilizing the legume dragon tongue bean waste peel and assessment of their multiple biological activities. The synthesized DtbP-AgNPs could serve as a potential candidate in the pharmaceutical industries in the formulation of drugs for the treatment of several medical ailments concerning cancer, diabetes, etc.

Green Synthesis Using Klebsiella pneumoniae as well as its Execution onto Textiles for Microbe Resistance

Microorganisms like bacteria and yeast and their use in the combination of nanoparticles is a basically a recent phenomenon. These microorganisms lessen the toxicity by decreasing the ions of metal or through the creation of complexes which are insoluble along with the metal’s ions (as metal sulfides) as colloidal elements. The present study focuses on bio-synthesis of silver nanoparticles by the bacterium Klebsiella pneumoniae. The reduction of AgNO3 to Ag nanoparticles was due to the extracellular production of the enzyme nitrate reductase by the K. pneumoniae into the medium. The particles were characterized by SEM. The biosynthesized Ag nanoparticles were padded on the fabrics of cotton by cure method of dry pad. The preliminary antimicrobial activity was performed by disc diffusion method against Escherichia coli and Staphylococcus aureus. The antimicrobial property of the treated fabrics were confirmed qualitatively and quantitatively by parallel streak (AATCC- 147) and challenge test (AATCC -100) respectively. SEM results revealed the form of the nano particles were in range of 50 - 60 nm. An area of inhibition of 7 mm as well as 5 mm were found against S.aureus and E.coli respectively by disc diffusion test. Parallel streak method also confirmed the anjinicrobial activity. The results of the challenge test revealed the fabrics treated with biosynthesized nanoparticles depicted 100% minimum point in comparision with S.aureus and 99% reduction against E.coli.

Biosynthesis of silver nanoparticles by Cyperus pangorei and its potential in structural, optical and catalytic dye degradation

The development of effective photocatalyst through green and eco-friendly approach has become a great concern for the light-induced degradation of organic pollutant dyes. This article reports a simple, cost-effective, and a benign environmental biosynthesis of Ag nanoparticles (NPs) using Cyperus pangorei, a plant extract with three different concentrations of AgNO3 in aqueous media. The synthesized silver nanoparticles were performed ultraviolet–visible spectroscopy (UV–Vis), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), photoluminescence (PL), transmission electron microscope (TEM), energy-dispersive X-ray spectroscopy (EDX) and X-ray photoelectron spectroscopy (XPS). The surface plasmon resonance (SPR) peak at 437 nm in UV–Vis spectroscopy confirmed the reduction of Ag+ ions into Ag nanoparticles. FTIR spectra revealed that plant extract could reduce/stabilize/capping to form Ag nanoparticles, and strong PL emission spectra tend to exhibit higher photocatalytic activity. The structural information is derived from XRD and TEM, which can exhibit the FCC structure and polydisperse with the spherical shape. EDX addresses the presence of Ag constitute. XPS confirmed the Ag nanoparticles in characteristic silver peaks, plant extract derivatives, and their oxidative states’ binding energy. The photocatalytic activity of Ag nanoparticles against dye Rhodamine B (Rh-B) under ultraviolet irradiation with periodic interval and pseudo-first-order kinetics were also studied. The obtained results show that the synthesized Ag nanoparticles can degrade dye (Rh-B) up to 86% within 2 h of irradiation time. Furthermore, the present study suggests that the biosynthesized Ag nanoparticles could be potential photocatalysts against various industrial dyes as well as C. pangorei; plant extract can be usto modify and develop more efficient nano-photocatalyst for other application.

Optical, structural, and antibacterial properties of biosynthesized Ag nanoparticles at room temperature using Azadirachta indica leaf extract

We report an enhancement of antibacterial properties of Ag nanoparticles (NPs) synthesized at room temperature using leaf extract of Azadirachta indica (Neem) following green synthesis route. To study such antibacterial properties Ag NPs of sizes within 9 nm to 17 nm were synthesized by varying the concentration of Neam leaf extract (NLE). The NP size and size distribution were seen to increase and decrease, respectively, with increase in NLE concentration. Also Ag NPs having a fixed size (~26 nm) was also synthesized by varying the precursor (AgNO3) concentration. It is noticed that concentration of NLE has significant effects on the control of NP size as well as size distribution whereas there is almost no role of precursor concentration of the NP size. All the Ag NPs are found to have face-centred-cubic crystal structure with preferential growth along (111) plane which is stable one. The peak of X-ray diffraction at ~32.4° (2θ value), which is prominent for low concentrations of NLE and precursor, is identified as (101) plane of Ag crystal. The generation and growth of Ag NPs had also been confirmed using electron microscopic studies. These Ag NPs show prominent surface plasmon resonance (SPR) absorption at ~ 420 nm confirming again the genesis of Ag NPs. The SPR peak shifts towards longer wavelength (redshift) with a corresponding reduction in full width at half maximum with increase in NP size. All of the samples containing Ag NPs show a broad blue photoluminescence (PL) emission at ~ 471 nm. Emission peak is seen to redshift with increase in NP size and is consistent with the optical absorption data. Such PL emission is argued as due to interband transition or plasmon luminescence. Being biocompatible of the green synthesis process, antibacterial properties of these Ag NPs were studies in details considering all the samples (with varied NP size for one set and with fixed NP size for other set of samples). As per our knowledge this is the first report of size related total study of Ag NPs, showing increased antibacterial effect as size decreased and equal antibacterial effect as size equals. It is found that smaller Ag NPs has enhanced antibacterial effects due to large surface area to volume ratio in comparison with bigger sized Ag NPs.