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Biosynthesis of noble metal nanoparticles is a vast developing area of research. In the present study, silver nanoparticles (Ag-NPs) are synthesized from aqueous silver nitrate through a simple and biosynthetic route using aqueous extract of Entada spiralis stem powder, which acted simultaneously as a reductant and stabilizer. The prepared samples are characterized using UV-visible, XRD, TEM, SEM, EDX, zeta potential and FTIR techniques. The formation of Ag-NPs is evidenced by the appearance of the signature brown color of the solution and UV-Vis spectra. Formation of E. spiralis/Ag-NPs is determined by UV-Vis spectroscopy, where surface plasmon resonance (SPR) absorption maxima can be observed at 400-450 nm from the UV-Vis spectrum at moderate temperature (~ 52 °C). The XRD analysis shows that the Ag-NPs at moderate temperature have a face-centered cubic structure (FCC). Well-dispersed Ag-NPs with anisotropic and isotropic morphology for E. spiralis/Ag-NPs at room and moderate temperature, with sizes of around 39.82 and 17.56 nm, are observed in TEM images. The SAED pattern exhibits the cubic lattice structure for Ag-NPs, and the d-spacing value of the crystalline structure of Ag-NPs measures around ~ 0.14 nm, which is attributed to the Ag-NPs of the (220) cubic plain at an angle of 64.78°. The spherical shapes of Ag-NPs with proper distribution for both reaction temperatures are observed in SEM images. The FTIR analysis reveals the main functional groups in the E. spiralis stem powder extract involved in the binding of Ag-NPs. The overall performance of the biosynthesis of Ag-NPs indicates that the formation of Ag-NPs using E. spiralis stem powder extract is temperature-dependent. [ABSTRACT FROM AUTHOR]

Green methods are a safer alternative to natural chemical and physical methods for the synthesis of silver nanoparticles (Ag-NPs), due to their being environmentally friendly and cost effective. This study offers a new green approach using ultrasound irradiation as the reducing agent and seaweed Kappaphycus alvarezii ( K. alvarezii) as the natural bio-media. The seaweed K. alvarezii/Ag-NPs was characterised by ultraviolet-visible (UV-vis), X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscope with energy dispersive X-ray (FESEM-EDX), zeta potential, and Fourier transform infrared (FTIR) studies. UV-vis shows that surface plasmon resonance (SPR) arises from this solution due to the combined oscillations from the nanoparticles. The XRD study indicates the crystalline nature of the Ag-NPs. From the TEM images, the Ag-NPs are almost spherical with an average diameter of 11.78 nm. The FTIR spectrum provides adequate evidence of phytochemicals stabilising the nanoparticles. Synthesised Ag-NPs were successfully obtained using this green method. [ABSTRACT FROM AUTHOR]

The synthesis of silver nanoparticles (Ag-NPs) was achieved by a simple green chemistry procedure using sodium alginate (Na-Alg) under ultrasonic radiation as a stabilizer and physical reducing agent. The effect of radiation time on the synthesis of Ag-NPs was carried out at room temperature until 720 min. The successful formation of Ag-NPs has been confirmed by UV-Vis, XRD, TEM, FESEM-EDX, zeta potential, and FT-IR analyses. The surface plasmon resonance band appeared at the range of 452–465 nm that is an evidence of formation of Ag-NPs. The XRD study showed that the particles are crystalline structure in nature, with a face-centered cubic (fcc) structure. The TEM study showed the Ag-NPs have average diameters of around 20.16–22.38 nm with spherical shape. The FESEM-EDX analysis confirmed the spherical shape of Ag-NPs on the surface of Alg and the element of Ag with the high purity. The zeta potential showed high stability of Alg/Ag-NPs especially after 720 min irradiation with value of −67.56 mV. The FT-IR spectrum confirmed that the Ag-NPs have been capped by the Alg with van der Waals interaction. The Alg/Ag-NPs showed the antibacterial activity against Gram-positive and Gram-negative bacteria. These suggest that Ag-NPs can be employed as an effective bacteria inhibitor and can be applied in medical field. [ABSTRACT FROM AUTHOR]

A green sonochemical method was developed for preparing silver nanoparticles (Ag-NPs) in κ-carrageenan in different concentrations of AgNO. The κ-carrageenan was used as an eco-friendly stabilizer and ultrasonic irradiation as a green reducing agent. The number of Ag-NPs increased with increasing concentrations of AgNO. Formation of Ag/κ-carrageenan was determined by UV-visible spectroscopy where the surface plasmon absorption maximum was observed at 410-416 nm. XRD analysis showed the Ag-NPs are of a face-centered cubic structure. TEM images showed the well-dispersed Ag-NPs with an average particle size <5 nm. SEM images showed the spherical shape of the Ag-NPs. The FT-IR spectrum indicated the presence of κ-carrageenan in capping the Ag-NPs. The use of photo irradiation provides a green and economic method features to the synthesis reported in this study. [ABSTRACT FROM AUTHOR]

The sonochemical method as a green method for the preparation and size control of silver nanoparticles (Ag-NPs) formed in κ-carrageenan has been developed. κ-carrageenan was chosen because it is an eco-friendly stabilizer and ultrasonic irradiation reducing agent. Formations of Ag/κ-carrageenan were determined by electronic spectroscopy where the surface plasmon absorption maxima were observed at 437-412 nm. The FT-IR spectrum indicated the presence of κ-carrageenan in capping with Ag-NPs. The XRD analysis proved that the Ag-NPs were of a face-centered cubic structure. TEM images displayed well-dispersed Ag-NPs with an average particle size of less than 10 nm. SEM images indicated the spherical shape of the Ag-NPs. [ABSTRACT FROM AUTHOR]

Silver nanoparticles (Ag NPs) have been synthesized by using a chemical reducing method in the external space of talc layers as a solid support at room temperature. NaBH and AgNO were used as a reducing agent and silver precursor, respectively. The interlamellar space limits were without many changes and, therefore, Ag NPs formed on the exterior surface of talc composites with mean diameters 7.60-13.11 nm for different silver nitrate concentrations. The antibacterial effects of different sizes of Ag NPs in talc were investigated against Gram-positive (i.e. Staphylococcus aureus and methicillin-resistant S. aureus) and Gram-negative (i.e. Escherichia coli) bacteria by the disk diffusion method using Mueller-Hinton Agar. The AgNO was found to have significant antibacterial activity against Ag NPs that did not indicate any antibacterial effects. These results showed that Ag NPs entrapped in the surface of talc layers cannot be used as effective growth inhibitors in different biological systems. [ABSTRACT FROM AUTHOR]

It is believed of great interest to incorporate silver nanoparticles (Ag-NPs) into stable supported materials using biological methods to control the adverse properties of nanoscale particles. In this study, in-situ biofabrication of Ag-NPs using Entada spiralis (E. spiralis) aqueous extract in Ceiba pentandra (C. pentandra) fiber as supporting material was used in which, the E. spiralis extract acted as both reducing and stabilizing agents to incorporate Ag-NPs in the C. pentandra fiber. The properties of Ag-NPs incorporated in the C. pentandra fiber (C. pentandra/Ag-NPs) were characterized using UV-visible spectroscopy (UV-vis), X-ray Diffraction (XRD), Field Emission Transmission Electron Microscope (FETEM), Scanning Electron Microscope (Scanning Electron Microscope (SEM), Energy Dispersive X-ray (EDX), Brunauer-Emmett-Teller (BET), Thermogravimetric (TGA) and Fourier Transform Infrared (FTIR) analyses. The average size of Ag-NPs measured using FETEM image was 4.74 nm spherical in shape. The C. pentandra/Ag-NPs was easily separated after application, and could control the release of Ag-NPs to the environment due to its strong attachment in C. pentandra fiber. The C. pentandra/Ag-NPs exposed good qualitative and quantitative antibacterial activities against Staphylococcus aureus (ATCC 25923), Enterococcus faecalis (ATCC 29212), Escherichia coli (ATCC 25922) and Proteus vulgaris (ATCC 33420). The dye catalytic properties of C. pentandra/Ag-NPs revealed the dye reduction time in which it was completed within 4 min for 20 mg/L rhodamine B and 20 min for 20 mg/L methylene blue dye, respectively. Based on the results, it is evident that C. pentandra/Ag-NPs are potentially promising to be applied in wound healing, textile, wastewater treatment, food packaging, labeling and biomedical fields. [ABSTRACT FROM AUTHOR]

In this study, a comparative study of effect using honey on copper nanoparticles (Cu-NPs) via simple, environmentally friendly process and inexpensive route was reported. Honey and ascorbic acid act as stabilizing and reducing agents with the assistance of sonochemical method. The products were characterized using UV–visible (UV–vis) spectroscopy, X-Ray Diffraction (XRD), High-Resolution Transmission Electron Microscopy (HRTEM), Field-Emission Scanning Electron Microscopy (FESEM) and Fourier Transform Infrared (FTIR) spectroscopy. The reddish brown colour demonstrated the formation of Cu-NPs and UV–visible proved the plasmon resonance of Cu-NPs. XRD also confirmed a highly pure Cu-NPs obtained with absence of copper oxide in which the structure is crystalline. The spherical size of the Cu-NPs was acquire in the presence of honey which is 3.68 ± 0.78 nm with narrow particle distribution. The antibacterial activity was seen against gram-positive and gram-negative bacteria which are Enterococcus faecalis (E. faecalis) and Escherichia coli (E. coli). At higher concentration of Cu-NPs, they were more effective in killing both bacteria. The Cu-NPs without and with honey exhibited toxicities toward normal and cancerous cells. However, Cu-NPs without honey showed more potent killing activity against normal and cancer cells. Unlabelled Image • Honey as capping and reducing agent for Cu-NPs • Ultrasonic irradiation assistance reduced the time of reaction. • Cu-NPs show potential antibacterial against gram positive and negative bacteria. • Cytotoxic of Cu-NPs toward CCD 112 and HCT 116 are reported in this study. [ABSTRACT FROM AUTHOR]

Discovery of a potent drug nanocarrier is crucial for cancer therapy in which drugs often face challenges in penetrating efficiently into solid tumours. Here, biosynthesis of silver nanoparticles (AgNPs) using a waste material, Garcinia mangostana (GM) fruit peel extract is demonstrated. The best condition for AgNPs synthesis was with 0.5 g of peel extract, 7.5 mM silver nitrate at 45 °C, ~pH 4 for 16 h. The synthesized AgNPs were spherical and 32.7 ± 5.7 nm in size. To test its efficiency to be used as drug carrier, plant-based drug, protocatechuic acid (PCA) was used as a test drug. AgNPs loaded with PCA (AgPCA) resulted in 80% of inhibition at 15.6 µg/mL as compared to AgNPs which only killed 5% of HCT116 colorectal cells at same concentration. The IC50 of AgNPs and AgPCA for HCT116 were 40.2 and 10.7 µg/mL, respectively. At 15.6 µg/mL, AgPCA was not toxic to the tested colon normal cells, CCD112. Ag-based drug carrier could also potentially reduce the toxicity of loaded drug as the IC50 of PCA alone (148.1 µg/mL) was higher than IC50 of AgPCA (10.7 µg/mL) against HCT116. Further, 24-h treatment of 15.6 µg/mL AgPCA resulted in loss of membrane potential in the mitochondria of HCT116 cells and increased level of reaction oxygen species (ROS). These could be the cellular killing mechanisms of AgPCA. Collectively, our findings show the synergistic anticancer activity of AgNPs and PCA, and its potential to be used as a potent anticancer drug nanocarrier. [ABSTRACT FROM AUTHOR]

Green synthesis of silver nanoparticles is desirable practice. It is not only the required technique for industrial and biomedical purposes but also a promising research area. The aim of this study was to synthesize green curcumin silver nanoparticles (C-Ag NPs). The synthesis of C-Ag NPs was achieved by reduction of the silver nitrate (AgNO3) in an alkaline medium. The characterizations of the prepared samples were conducted by ultraviolet visible (UV-vis) spectroscopy, powder X-ray diffraction (PXRD), field emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED) and zeta potential (ZP) analyses. The formation of C-Ag NPs was evaluated by the dark color of the colloidal solutions and UV-vis spectra, with 445 nm as the maximum. The size of the crystalline nanoparticles, recorded as 12.6 ± 3.8nm, was confirmed by HRTEM, while the face-centered cubic (fcc) crystallographic structure was confirmed by PXRD and SAED. It is assumed that green synthesized curcumin silver nanoparticles (C-Ag NPs) can be efficiently utilized as a strong antimicrobial substance for food and meat preservation due to their homogeneous nature and small size. [ABSTRACT FROM AUTHOR]

Broiler meat can provide an appropriate environment for the microbial intensification, resulting in the lipid and protein oxidation and physico-chemical degradation. The utilisation of the anti-oxidants prevents meat degradation and human health challenges by preventing meat physico-chemical characteristics. Pullulan active packaging incorporated with green silver nanoparticles, as anti-oxidants, has not been reported in broiler meat preservation. Therefore, the impact of pullulan active packaging, incorporated with curcumin and pullulan mediated silver nanoparticles (C-AgNPs, P-AgNPs) on broiler meat was determined in the current study for 14 days of refrigerated storage at 4 ± 1 °C. A total of 120 broiler birds were reared for clean meat production and divided into 4 treatment groups (PF-CTRL, PF-C-AgNPs, PF-P-AgNPs, PF-M-AgNPs). Pullulan active packaging maintained meat textural attributes and pigment stability and breast muscle pH (6.11). Broiler meat treated with pullulan active packaging incorporated with curcumin arbitrated AgNPs (PF-C-AgNPs) indicated significantly higher oxidative stability (p =.000), water holding capacity (p =.002), expressible fluids (p =.000), and shear force values (p =.000) along with significantly lower cooking losses (p =.000), pH (p =.000), and shear force energy (p =.000) as compared to the control (CTRL) and other treatment groups. Broiler breast meat samples treated with pullulan active packaging expressed a "lighter" appearance (53.61 ± 3.64) during the refrigerated storage of 14 days. Moreover, significant differences were recorded in the oxidative stability/MDA (mg/kg) concentrations amongst the controlled and the treated groups on day 7th (p =.000) and day 14th (p =.000) of refrigerated storage. The current study confirms that the pullulan active packaging, incorporated with curcumin arbitrated silver nanoparticles (PF-C-AgNPs) followed by pullulan active meat packaging incorporated with pullulan mediated silver nanoparticles (PF-P-AgNPs) maintained the textural and physico-chemical meat attributes along with minimal oxidative rancidity in 14 days of storage. It is concluded that PF-C-AgNPs and PF-P-AgNPs can be a safer antioxidant alternate to preserve broiler meat quality and oxidative stability with a prolonged shelf life. Pullulan active meat packaging, incorporated with C-AgNPs and P-AgNPs, should be considered as green and bio-degradable substitution of the hazardous synthetic antioxidant packaging. Pullulan active meat packaging (PF-C-AgNPs, PF-P-AgNPs) is able to maintain the textural characteristics, compositional integrity, and physico-chemical attributes of broiler meat. Broiler meat treated with PF-C-AgNPs and PF-P-AgNPs reflects better oxidative stability with prolonged shelf life. [ABSTRACT FROM AUTHOR]

Background: Green approach in synthesizing metal nanoparticles has gain new interest from the researchers as metal nanoparticles were widely applied in medical equipment and household products. The use of plants in the synthesis of nanoparticles emerges as a cost effective and eco-friendly approach. A green synthetic route for the production of stable silver nanoparticles (Ag-NPs) by using aqueous silver nitrate as metal precursor and Artocarpus elasticus stem bark extract act both as reductant and stabilizer is being reported for the first time. Results: The resultant Ag-NPs were characterized by UV-vis spectroscopy, powder X-Ray diffraction, transmission electron microscopy (TEM), scanning electron microscopy (SEM), and Fourier-transform infra-red (FT-IR). The morphological study by TEM and SEM shows resultant Ag-NPs in spherical form with an average size of 5.81 ± 3.80, 6.95 ± 5.50, 12.39 ± 9.51, and 19.74 ± 9.70 nm at 3, 6, 24, and 48 h. Powder X-ray diffraction showed that the particles are crystalline in nature, with a face-centered cubic structure. The FT-IR spectrum shows prominent peaks appeared corresponds to different functional groups involved in synthesizing Ag-NPs. Conclusions: Ag-NPs were synthesized using a simple and biosynthetic method by using methanolic extract of A. elasticus under room temperature, at different reaction time. The diameters of the biosynthesis Ag-NPs depended on the time of reaction. Thus, with the increase of reaction time in the room temperature the size of Ag-NPs increases. From the results obtained in this effort, one can affirm that A. elasticus can play an important role in the bioreduction and stabilization of silver ions to Ag-NPs. [ABSTRACT FROM AUTHOR]

Artificial neural networks (ANNs) are computational tools that have found comprehensive utilization in solving many complex real world problems. Major benefits in using ANNs are their remarkable information-processing characteristics pertinent mainly to high parallelism, nonlinearity, fault and noise tolerance, and learning and generalization capabilities. An ANN approach is used to model the size of silver nanoparticles (Ag-NPs) in montmorillonite/chitosan bionanocomposites layers as a function of the silver nitrate concentration, reaction of temperature, chitosan percentage, and d-spacing of clay layers. The best ANN model is found and this final model is capable of predicting the size of nanosilver for a wide range of conditions with a mean absolute error of less than 0.004 and a regression error of about 1. Results obtained showed good ability predictive of neural network model for the prediction of the size of Ag-NPs in chemical reduction methods. [ABSTRACT FROM AUTHOR]

The production of pure silver nanoparticles (Ag-NPs) with unique properties remains a challenge even today. In the present study, the synthesis of silver nanoparticles (Ag-NPs) from natural pullulan (PL) was carried out using a radiation-induced method. It is known that pullulan is regarded as a microbial polysaccharide, which renders it suitable to act as a reducing and stabilizing agent during the production of Ag-NPs. Pullulan-assisted synthesis under gamma irradiation was successfully developed to obtain Ag-NPs, which was characterized by UV-Vis, XRD, TEM, and Zeta potential analysis. Pullulan was used as a stabilizer and template for the growth of silver nanoparticles, while gamma radiation was modified to be selective to reduce silver ions. The formation of Ag-NPs was confirmed using UV–Vis spectra by showing a surface plasmon resonance (SPR) band in the region of 410–420 nm. As observed by TEM images, it can be said that by increasing the radiation dose, the particle size decreases, resulting in a mean diameter of Ag-NPs ranging from 40.97 to 3.98 nm. The XRD analysis confirmed that silver metal structures with a face-centered cubic (FCC) crystal were present, while TEM images showed a spherical shape with smooth edges. XRD also demonstrated that increasing the dose of gamma radiation increases the crystallinity at a high purity of Ag-NPs. As examined by zeta potential, the synthesized Ag-NP/PL was negatively charged with high stability. Ag-NP/PL was then analysed for antimicrobial activity against Staphylococcus aureus, and it was found that it had high antibacterial activity. It is found that the adoption of radiation doses results in a stable and green reduction process for silver nanoparticles. [ABSTRACT FROM AUTHOR]

Nanoparticles (NPs) are, frequently, being utilized in multi-dimensional enterprises. Silver nanoparticles (AgNPs) have attracted researchers in the last decade due to their exceptional efficacy at very low volume and stability at higher temperatures. Due to certain limitations of the chemical method of synthesis, AgNPs can be obtained by physical methods including sun rays, microwaves and ultraviolet (UV) radiation. In the current study, the synthesis of pullulan mediated silver nanoparticles (P-AgNPs) was achieved through ultraviolet (UV) irradiation, with a wavelength of 365 nm, for 96 h. P-AgNPs were formed after 24 h of UV-irradiation time and expressed spectra maxima as 415 nm, after 96 h, in UV-vis spectroscopy. The crystallographic structure was "face centered cubic (fcc)" as confirmed by powder X-ray diffraction (PXRD). Furthermore, high resolution transmission electron microscopy (HRTEM) proved that P-AgNPs were covered with a thin layer of pullulan, with a mean crystalline size of 6.02 ± 2.37. The average lattice fringe spacing of nanoparticles was confirmed as 0.235 nm with quasi-spherical characteristics, by selected area electron diffraction (SAED) analysis. These green synthesized P-AgNPs can be utilized efficiently, as an active food and meat preservative, when incorporated into the edible films. [ABSTRACT FROM AUTHOR]

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