Presence Of AgNPs Research Articles

Synthesis of silver nanoparticles from Indian red yeast rice and its inhibition of biofilm in copper metal in cooling water environment.

The development of environmentally acceptable benign techniques using purely natural methods is a cost-effective procedure with long-term benefits in all areas. With this consideration, myco synthesized silver nano particles (AgNPs) were studied and it acted as an impending corrosion inhibitor in the environment. Initially, AgNPs were evaluated by physical and surface characterizations and this evidence demonstrated that RYRE's water-soluble molecules played an essential role in the synthesis of AgNPs in nano spherical size. The myco synthesized of AgNPs has showed an antibacterial activity against corrosive bacteria in cooling water system (CWS). Hence, the AgNPs were used in biocorrosion studies as an anticorrosive agent along with AgNO3 and RYRE was also checked. For this experiment, the copper (Cu) metal (CW024) which is commonly used was selected, the result of corrosion rate was decreased, and inhibition efficiency (82%) was higher in the presence of AgNPs in system IV. Even though, AgNO3 and RYRE had contributed significant inhibition efficiency on Cu at 47% and 61%, respectively. According to XRD, the reaction of AgNPs on Cu metal resulted in the formation of a protective coating of Fe2O3 against corrosion. EIS data also indicated that it could reduce the corrosion on the Cu metal surface. All of these findings point out the possibility that the myco-synthesized AgNPs were an effective copper metal corrosion inhibitor. As a result, we encourage the development of myco-synthesized AgNPs, which could be useful in the industrial settings.

Citrus sinensis leaf aqueous extract green-synthesized silver nanoparticles: Characterization and cytotoxicity, antioxidant, and anti-human lung carcinoma effects

The present work demonstrates the synthesis of Ag nanoparticles (Ag NPs) by using aqueous extract of Citrus sinensis as green reductant and capping agent without any toxic reagent. Physicochemical characteristics of the said nanoparticles were elucidated by field emission scanning electron microscopy (FESEM), fourier transform infrared spectroscopy (FTIR), and ultraviolet–visible spectroscopy (UV-Vids) techniques. The biogenic Ag NPs are uniformly globular. The Ag NPs has been explored biologically in the anticancer and antioxidant assays. In the cellular and molecular part of the recent study, the treated cells with Ag NPs were assessed by MTT assay for 48 h about the cytotoxicity and anti-human lung carcinoma properties on normal (HUVEC) and lung carcinoma cell lines i.e. NCI-H661, HLC-1, NCI-H1563, LC-2/ad, NCI-H1299, and PC-14. The viability of malignant lung cell line reduced dose-dependently in the presence of Ag NPs. The IC50 of Ag NPs were 82, 139, 170, 66, 62, and 50 µg/mL against NCI-H661, HLC-1, NCI-H1563, LC-2/ad, NCI-H1299, and PC-14 cell lines, respectively. In the antioxidant test, the IC50 of Ag NPs and vitamin E against 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radicals were 21 and 15 µg/mL, respectively. After clinical study, Ag NPs containing Citrus sinensis leaf aqueous extract may be used to formulate a new chemotherapeutic drug or supplement to treat the several types of human lung adenocarcinoma.

Silicon Nanowires Decorated with Silver Nanoparticles for Photoassisted Hydrogen Generation

Highly n-doped silicon nanowires (SiNWs) decorated with silver nanoparticles (AgNPs) at the top, middle, and bottom were produced using electroless silver deposition (ELD), silver mirror reaction (MR), and native AgNPs as a reference, respectively. Subsequently, hydrogen generation on SiNWs decorated with and without AgNPs was evaluated. Our results show that SiNWs decorated with native and MR AgNPs produce the highest and the lowest hydrogen amount under white light irradiation in 3 h, respectively. Moreover, for SiNWs with native AgNPs, the morphology of SiNWs after hydrogen generation was almost the same as the original array of SiNWs before hydrogen release, even after 24 h in water/ethanol (4:1; v/v) solution. However, the geometry of SiNWs decorated without and with AgNPs by ELD and MR was collapsed after hydrogen evolution. The detailed surface studies show that the sidewall surface of SiNWs with native AgNPs has a rougher topology and formed a stable layer of SiOx in water. Our observations strongly suggest that two hydrogen generation possibilities, i.e., SiNW oxidation and photostimulation, are jointly responsible for the efficient hydrogen generation. Additionally, the presence of AgNPs on the sidewall of the SiNW matrix can enhance the hydrogen generation rate. Our results open novel perspectives for the effective hydrogen generation based on nanostructured silicon.

Biogenic silver/silver chloride nanoparticles inhibit human cancer cells proliferation in vitro and Ehrlich ascites carcinoma cells growth in vivo

Silver/silver chloride nanoparticles (Ag/AgCl-NPs) were synthesized for the first time from the herbal Geodorum densiflorum rhizome extracts and characterized by different techniques. The surface plasmon resonance peak at 455 nm was observed in the UV–Visible spectrum, the average particle size of 25 nm was determined by SEM, XRD reflection peaks (28.00°, 32.42°, 38.28°, 46.38°, 54.94°, 57.60°, 64.64°, and 67.48°) indicated the presence of Ag-NPs and AgCl-NPs, heat stability was confirmed by TGA and FTIR analysis indicated the presence of alcohol/phenol, alkanes, primary amines, nitro compounds, alkyl chloride functional groups. The synthesized Ag/AgCl-NPs, previously synthesized Kaempferia rotunda and Zizyphus mauritiana mediated Ag/AgCl-NPs separately inhibited the proliferation of BxPC-3 cells with the IC50 values of 7.8, 17.1, and 20.1 µg/ml, respectively. In the case of MCF-7 cells, the IC50 values of G. densiflorum- Ag/AgCl-NPs and K. rotunda-Ag/AgCl-NPs were 21.5 and 23.5 µg/ml, respectively. Whereas the IC50 of G. densiflorum-Ag/AgCl-NPs was 28.0 µg/ml against glioblastoma stem cells (GSCs). Induction of apoptosis in GSCs, BxPC-3 and MCF-7 cells was noted followed by NPs treatment. In GSCs, the expression level of NFκB, TNFα, p21, and TLR9 genes were upregulated after treatment with G. densiflorum-Ag/AgCl-NPs while in the MCF-7 cells, the expression of p53, FAS, Caspase-8 and -9, NFκB, MAPK, JNK and p21 genes were increased. G. densiflorum-Ag/AgCl-NPs inhibited 60% and 95% of EAC cells growth at the doses of 2 and 4 mg/Kg/day after intraperitoneal treatment with five consequent days, respectively. A remarkable improvement of hematological parameters with the decreased average tumor weight and increase of 75% life span of G. densiflorum-Ag/AgCl-NPs treated mice were observed. Altogether, this study reported for the first time in vitro anticancer activity of biogenic G. densiflorum-Ag/AgCl-NPs against GSC cells along with MCF-7 and BxPC-3 cells and in vivo anticancer properties against EAC cells.

1,4-bis[β-(2-benzoxazoly1) vinyl] benzene (BBVB) laser dye and sodium salt of meso-tetrakis (4-sulfonatophenyl) porphyrin (TPPS); spectroscopic investigation and DFT, NBO and TD-DFT calculations

Excitation energy transfer (ET) from 1,4-bis[β-(2-benzoxazoly1) vinyl] benzene as a donor to sodium salt of meso-tetrakis (4-sulfonatophenyl) porphyrin (TPPS) as an acceptor was investigated in the absence and presence of metallic silver nanoparticles (Ag NPs). The emission intensities and Stern –Volmer constants (KSV) of the ET processes were calculated in methanol (MeOH) and 40% ethylene glycol (EG) as 5.87 × 104 M−1 and 6.27 × 104 M−1, respectively. KSV value in the presence of Ag NPs was 1.028 × 105 M−1 in methanol, much higher than in absence of NPs. This is attributed to the role of Ag NPs in increasing the strength of the donor–acceptor interactions. These results denote the use of Ag NPs for measuring the proximity of large biomolecules and ET-based assays. Also, the critical ET distance Ro was calculated as 36 Å. This magnitude is higher than the common value of 10 Å for the collisional ET mechanism. This high Ro value indicates the underlying mechanism as long-range dipole–dipole interaction. The BBVB, TPPS, and BBVB/TPPS molecular structures (MSs) were optimized using the DFT/ B3LYP/6-311G (d) method for the quantum calculations. The calculated electronic UV–Vis absorption spectra for BBVB and BBVB/TPPS MSs in MeOH were examined by the time-dependent density functional theory (TD-DFT) at CAM-B3LYP/6-311G++(3d,3p) level. Interestingly, all theoretical results of BBVB and BBVB/TPPS molecules were highly matched with the experimental results. Furthermore, the Natural Bond Orbital (NBO) analyses for BBVB and BBVB/TPPS MSs were obtained using the B3LYP/6-311G(d) level of theory.

Biosynthesis of silver nanoparticles using three different fruit extracts: Characterization, formation mechanism and estrogen removal

Plant-mediated synthesis of silver nanoparticles (Ag NPs) is a green and economically viable method, which can offer numerous benefits over traditional chemical and physical methods. In this paper, three fruit extracts (tomato, orange, and grapefruit) served simultaneously as stabilizing and reducing agents during the biosynthesis of Ag NPs. The formation of Ag NPs, were monitored using the UV–visible absorption spectra of Ag NPs which exhibited three distinct bands centered at 439, 413, and 410 nm. SEM and TEM analysis indicated that these bands corresponded to three distinct spherical-shaped Ag NPs having average particle sizes of 73, 24, and 31 nm, respectively. XRD and EDS spectral analyses were used to verify the degree of crystallinity, nanostructure, and presence of Ag NPs. Advanced analysis using XPS, FTIR, and GC-MS indicated that the Ag NPs were coated with a variety of organic compounds including acids, aldehydes, esters, and ketones, indicating that fruit derived phytochemicals had a significant role in synthesis, and subsequently a mechanism of Ag NPs formation was proposed. The fabricated nanoparticles were also successfully used in Fenton-like oxidation for the environmental remediation of estrone and estriol, with removal efficiencies of 52.1 and 35.9%, respectively.

The role of Ag NPs in PVA electrospun NFs for ultra-high sensitivity photodetector

This work aimed to produce PVA and PVA/Ag nanofibers ultra-high sensitivity photodetector by electrospinning. The electrospinning process was used to successfully prepare PVA nanofibers and a PVA-Ag nanofiber composite. FE-SEM, XRD, UV, I-V characterizations are used to study the morphological, structural, optical, and electrical properties of the material. In contrast, the PVA-Ag nanofiber composite film displayed a cubic structure with favored orientation (200) that indicated the presence of Ag NPs in the PVA-Ag nanofibers film. While the optical energy gap for PVA was 3.96 eV, it was only 2.14 eV for PVA-Ag nanofibers composite film, making this composite sensitive to visible light, particularly green light at 550 nm with a 65% photosensitivity. The optical energy gap of PVA-Ag nanofibers composite was used to tailor this film from the ultraviolet to the visible spectrum.

Bacillus mojavensis, a Metal-Tolerant Plant Growth-Promoting Bacterium, Improves Growth, Photosynthetic Attributes, Gas Exchange Parameters, and Alkalo-Polyphenol Contents in Silver Nanoparticle (Ag-NP)-Treated Withania somnifera L. (Ashwagandha).

Discharge of nanoparticles (NPs) into aquatic and terrestrial ecosystems during manufacturing processes and from various commercial goods has become a significant ecotoxicological concern. After reaching soil systems, NPs cause deleterious effects on soil fertility, microbial activity, and crop productivity. Taking into consideration the medicinal importance of Withania somnifera (L.) (ashwagandha), the present study assessed the potential hazards of silver nanoparticles (Ag-NPs) and the toxicity amelioration by a metal-tolerant plant growth-promoting rhizobacterium (PGPR). Bacillus mojavensis BZ-13 (NCBI accession number MZ950923) recovered from metal-polluted rhizosphere soil, tolerated an exceptionally high level of Ag-NPs. The growth-regulating substances synthesized by B. mojavensis were increased with increasing concentrations (0–1000 μg mL–1) of Ag-NPs. Also, strain BZ-13 had the ability to form biofilm, produce alginate and exopolysaccharides (EPSs), as well maintain swimming and swarming motilities in the presence of Ag-NPs. Soil application of varying concentrations of Ag-NPs resulted in a dose-related reduction in growth and biochemical features of ashwagandha. In contrast, following soil inoculation, B. mojavensis relieved the Ag-NPs-induced phytotoxicity and improved plant productivity. Root, shoot length, dry biomass, and leaf area increased by 13, 17, 37, 25%, respectively, when B. mojavensis was applied with 25 mg/kg Ag-NPs when compared to noninoculated controls. Furthermore, the soil plant analysis development (SPAD) index, photosystem efficiency (Fv/Fm), PS II quantum yield (FPS II), photochemical quenching (qP), non-photochemical quenching (NpQ), and total chlorophyll and carotenoid content of BZ-13-inoculated plants in the presence of 25 mg Ag-NPs/kg increased by 33, 29, 41, 47, 35, 26, and 25%, respectively, when compared to noninoculated controls that were exposed to the same amounts of NPs. In addition, a significant (p ≤ 0.05) increase in 48, 18, 21, and 19% in withaferin-A (alkaloids), flavonoids, phenols, and tannin content, respectively, was recorded when plants were detached from bacterized and Ag-NP-treated plants. Leaf gas exchange parameters were also modulated in the case of inoculated plants. Furthermore, bacterial inoculation significantly decreased proline, lipid peroxidation, antioxidant enzymes, and Ag-NP’s absorption and build-up in phyto-organs. In conclusion, soil inoculation with B. mojavensis may possibly be used as an alternative to protect W. somnifera plants in soil contaminated with nanoparticles. Therefore, phytohormone and other biomolecule-synthesizing and NP-tolerant PGPR strains like B. mojavensis might serve as an agronomically significant and cost-effective remediation agent for augmenting the yield and productivity of medicinally important plants like ashwagandha raised in soil contaminated with nanoparticles in general and Ag-NPs in particular.

Can microplastics from personal care products affect stream microbial decomposers in the presence of silver nanoparticles?

Microplastics (MPs) are emerging contaminants of great concern due to their abundance and persistence over time in aquatic environments. However, studies on their impacts on freshwater organisms are scarce. In resemblance, silver nanoparticles (Ag-NPs) are incorporated into textiles and personal care products and are also classified as emerging contaminants. We used the leaf litter decomposition model system to investigate the effects of MPs from a commercially used personal care product, alone or in mixture with Ag-NPs, on the diversity and activities of freshwater microbial decomposers. We exposed stream microbial communities associated with leaf litter to increasing concentrations of MPs (polyethylene extracted from a personal care product; 100 μg L−1 up to 1 g L−1 5 concentrations plus 1 control) for 27 days in the absence or presence of Ag-NPs (0.1 mg L−1 and 1 mg L−1). The exposure to MPs, alone or in mixture with Ag-NPs, negatively affected fungal diversity and sporulation, with a reduction in leaf litter decomposition (Cohen's d > 1.5; r> 0.8; Bonferroni, P < 0.01). Shifts in community structure of sporulating fungi were observed, and effects were more pronounced in mixtures with Ag-NPs at the highest concentration. Mixtures of MPs with Ag-NPs (at the higher concentration) had the strongest impacts on extracellular enzymatic (β-glucosidase, Cohen's d > 1; r > 0.5; phenol oxidase, Cohen's d > 1; r > 0.4) activities (ANOVAs, P < 0.05). Apart from sporulation rates, observed toxicity in mixtures was lower than that expected based on individual toxicity effects, mainly for higher concentrations (Bonferroni, P < 0.05). Our study provided evidence of the potential harmful effects of MPs, alone or in mixtures with Ag-NPs, on the activities of aquatic fungi and on a key ecosystem process, determinant to organic matter turnover in streams.

Green Synthesis of Silver Nanoparticles using Plant Extracts and Their Applications for Water Purification and Anti-Diabetic Properties

The study reports the synthesis of silver nanoparticles (AgNPs) using green method where plant extracts of Turmeric, curry-leaves, Ashwagandha, Arjun, Aloe vera and Tulsi were used as reducing agents. Characterization was done using UV-Visible spectroscopy and Scanning electron microscopy. UV-Visible spectrum showed peak absorbance around 420nm and SEM-EDAX analysis confirmed the presence of AgNPs in a size range of 50-80nm. Ability of the synthesized AgNPs as an antimicrobial agent was studied and their use was extended to the treatment of contaminated water. It was found that 30μL of AgNPs effectively decontaminated water containing 103 CFU/mL E. coli within 10 minutes. The study also focuses on the effect of the nanoparticles on the growth of Saccharomyces cerevisiae as a model organism for eukaryotic cells. No significant effect on the growth of S. cerevisiae was observed. Effect of AgNPs on advanced glycation end-products (AGEs) was also studied. AGEs are formed due to non-enzymatic glycation in hyperglycemic conditions leading to secondary complications in diabetes. AgNPs synthesized using Ashwagandha, curry-leaves and Aloe vera showed anti-glycating properties in a concentration dependent manner. This suggests that these properties of AgNPs may be used in many environmental and therapeutic applications but their use should be regulated and studied in detail.

In silico modeling of the antagonistic effect of mercuric chloride and silver nanoparticles on the mortality rate of zebrafish (Danio rerio) based on response surface methodology.

In this study, in silico modeling was designed to examine the antagonistic effect of mercuric chloride (HgCl2) and silver nanoparticles (AgNPs) on the mortality rate of zebrafish (Danio rerio) based on response surface methodology (RSM). Adult zebrafish (Danio rerio) with an average weight of 0.75 ± 0.16g were used in this study. An interaction between HgCl2 and AgNPs was evaluated using DLS, TEM, and EDX mapping. In addition, RSM was applied to determine and predict the mortality rate of zebrafish induced by HgCl2 in the presence of non-lethal concentrations of AgNPs and to optimize dependent and independent variables. Following exposure to HgCl2, in vitro observations showed an increase in the hydrodynamic size of AgNPs and the formation of irregular nanoparticles. EDX mapping analysis also demonstrated the deposition of Hg ions on the surface of AgNPs, indicating the interaction between HgCl2 and AgNPs (i.e., the amalgamation of Hg and AgNPs). Moreover, in silico and in vivo findings illustrated that the mortality rate of zebrafish increased significantly in a concentration-dependent manner; however, the mortality rate reduced greatly in the presence of AgNPs during 96-h exposure. Statistically significant correlation and regression were also observed for the mortality rate between the actual and predicted values based on the ANOVA results, showing that the proposed model fits well. The most critical conditions of mortality rate were occurred by HgCl2 concentration of 0.23mg L-1 and AgNP concentration of 0.04mg L-1 that yielding maximum fish mortality rate of 96.541%. Additionally, the obtained value for model desirability was equal to 1.000 (i.e., the highest possible value). In conclusion, this statistical model could accurately describe the relationship between independent and dependent variables, and consequently boost substantially the experimental design of ecotoxicological studies by reducing the number of model organisms, toxic and chemical substances, time, and budget.

The Use of Silver Nanoparticles in Water Treatment, Wastewater Treatment and Recycling

The review paper deals with the use of silver nanoparticles (AgNPs) in water treatment and recycling systems and the presence of AgNPs in wastewater systems. In the water industry, AgNPs can be used in the water treatment process as new filter materials (layers applied to the membranes of various compositions) or as a gentle alternative to the existing drinking water disinfection (solar disinfection in combination with titanium). On the other hand, AgNPs also can be a certain risk to the ecosystem if they are released from such surface-treated materials or preparations into wastewater. The AgNPs, present in the wastewater, then penetrate to the wastewater treatment plants, where they can affect the treatment process itself, especially the sensitive biological nitrification process. Silver ions with antibacterial properties are effectively removed by wastewater treatment plants and no significant negative effect on the treatment process by higher concentrations of silver has been reported so far. With respect to the bioaccumulation capabilities of nanoparticles, it is important to focus primarily on assessing of the longer-term effects of AgNPs in the ecosystem and the aquatic environment.

Temperature-responsive hybrid nanomaterials based on modified halloysite nanotubes uploaded with silver nanoparticles

New temperature-responsive hybrid nanomaterials based on modified halloysite nanotubes (HNTs) containing grafted polymer brushes with silver nanoparticles have been successfully fabricated. We used a three steps process including synthesis of the initiating coatings onto HNTs surface, fabrication of the POEGMA – poly(oligo(ethylene glycol)ethyl ether methacrylate) grafted brushes and synthesis of the silver nanoparticles (AgNPs). The synthesis and properties of hybrid nanomaterials were studied by FT-IR, TGA and DLS methods. It is shown that the introduction of AgNPs, formed from 0.005 M AgNO3 solution leads to a significant reduction of low critical solution temperature (LCST) of the polymer layer from 29.7 to 21.6 °C. The samples fabricated from 0.05 M AgNO3 solution did not evidence a temperature-induced transition, despite of the contents of AgNPs obtained for both solutions are almost identical (≈ 4%w). The presence of AgNPs with sizes of ca. 20 nm was confirmed in the hybrids prepared from both AgNO3 concentrations by UV–vis spectroscopy, and electron microscopy. These temperature-responsive hybrid nanomaterials may be used for conservation of solid substrates, production of advanced medical facemasks, photothermal therapy against microorganisms and tumors etc.

The individual and combined effects of polystyrene and silver nanoparticles on nitrogen transformation and bacterial communities in an agricultural soil

The effects of emerging contaminants micro/nanoplastics (MPs/NPs) and silver nanoparticles (Ag NPs) on health have attracted universal concern throughout the world. However, it is unclear on the combined effects of MPs/NPs and Ag NPs on the biogeochemistry cycle such as nitrogen transformation and functional microorganism in the soil. In the present study, we conducted a 45-day soil microcosm experiment with polystyrene (PS) MPs/NPs and Ag NPs to investigate their combined impact on nitrogen cycling and the bacterial community. The results showed that MPs or NPs exerted limited effects on nitrogen transformation in the soil. The combined effects of PS MPs/NPs and Ag NPs were mainly caused by the presence of Ag NPs. However, PS NPs alleviated the inhibition of anammox and denitrification induced by Ag NPs via upregulating anammox-related genes and elevating nitrate and nitrite reductase activities. PS MPs + Ag NPs treatment significantly reduced bacterial diversity. PS MPs/NPs + Ag NPs increased the relative abundances of denitrifying Cupriavidus by 0.32% and 0.06% but decreased nitrogen-fixing functional microorganisms of Microvirga (by 2.05% and 2.24%), Bacillus (by 0.16% and 0.22%), and Herbaspirillum (by 0.14% and 0.07%) at the genus level compared with Ag NPs alone. The significant downregulation of nitrogen-fixing genes (K02586, K02588, and K02591) was observed in PS MPs/NPs + Ag NPs treatment compared to Ag NPs in the nitrogen metabolism pathway. Moreover, g-Lysobacter and g-Aquimonas were identified as biomarkers in PS MPs + Ag NPs and PS NPs + Ag NPs by LEfSe analysis. Our study sheds the light that changes of functional microorganism abundances contributed to the alteration of nitrogen transformation. Taking the particle size of plastics into account will be helpful to accurately assess the combined ecological risks of plastics and nanomaterial contaminants.

Preparation and Vibrio sp Antibacterial Activity of Silver Nanoparticles Mediated by Chromolaena odorata Leaf Extract using Different Temperatures

This research aims to synthesize silver nanoparticles (AgNPs) using Kirinyuh (Chromolaena odorata) leaf extract with different temperature and evaluate its activity in Vibrio sp.&#x0D; The synthesis was carried out by combining between silver nitrate solution and Kirinyuh leaf extract at room temperature (AgNPs 200) and hydrothermal process at 60oC (AgNPs 200*). Based on the results of LC-MS analysis, most of the chemical content of an extract was a flavonoid group compound. The color of the solution changed from colorless to red-brown, and a new peak around 435 nm showed that silver nanoparticles have been successfully obtained. The hydrothermal process exhibits sharp peaks rather than without hydrothermal treatment. The silver nanoparticles have a definite crystalline structure. The FTIR spectroscopy analysis indicated the organic compound was responsible for capping and stabilizing agents. In addition,TEM analysis showed that AgNPs 200 and AgNPs 200* exhibited average particle size of 32.89 nm and 27.82 nm, respectively. The presence of AgNPs can enhance the zone of growth inhibition of Vibrio sp approximately 300% compared to Kirinyuh leaf extract. Silver nanoparticles is estimated to possess the potential to be further evolved and utilized to inhibit the growth of Vibrio sp bacteria in shrimp agriculture.

A mechanistic study of ciprofloxacin adsorption by goethite in the presence of silver and titanium dioxide nanoparticles

The adsorption behaviors of ciprofloxacin (CIP), a fluoroquinolone antibiotic, onto goethite (Gt) in the presence of silver and titanium dioxide nanoparticles (AgNPs and TiO2NPs) were investigated. Results showed that CIP adsorption kinetics in Gt with or without NPs both followed the pseudo-second-order kinetic model. The presence of AgNPs or TiO2NPs inhibited the adsorption of CIP by Gt. The amount of inhibition of CIP sorption due to AgNPs was decreased with an increase of solution pH from 5.0 to 9.0. In contrast, in the presence of TiO2NPs, CIP adsorption by Gt was almost unchanged at pHs of 5.0∼6.5 but was decreased with an increase of pH from 6.5 to 9.0. The mechanisms of AgNPs and TiO2NPs in inhibiting CIP adsorption by Gt were different, which was attributed to citrate coating of AgNPs resulting in competition with CIP for adsorption sites on Gt, while TiO2NPs could compete with Gt for CIP adsorption. Additionally, CIP was adsorbed by Gt or TiO2NPs through a tridentate complex involving the bidentate inner-sphere coordination of the deprotonated carboxylic group and hydrogen bonding through the adjacent carbonyl group on the quinoline ring. These findings advance our understanding of the environmental behavior and fate of fluoroquinolone antibiotics in the presence of NPs.

Decoration of graphene sheets with silver nanoparticles and their characterization

Graphene has been an emerging area of research since last decade. This fantastic material promises a wide variety of applications starting from electronics to biomedical fields. The properties of graphene can be enhanced by conjugating it with various other elements. The present work describes about the deposition of silver nano-particles via chemical synthesis onto in-house synthesized graphene nanosheets. It can be pointed out that application of infrared accelerates the synthesis process. Few layered graphene nanosheets (FLGNs) has been synthesized through electrochemical exfoliation technique. The colloidal graphene solution stabilized by citrate ions helps in the chemical reduction of AgNO3, which is essential in the formation of a nano-sized silver particulate layer (Ag NPs) over the graphene sheets. The presence of Ag NPs over the as-synthesized graphene was established by XRD, UV–VIS, FE-SEM and STM studies. The change in colloidal stability for the as-synthesized graphene and Ag NPs coated graphene was explained by the dynamic light scattering studies. The electronic characteristics of graphene coated Ag NPs was studied by scanning tunneling spectroscopy (STS) technique. The STS studies revealed that graphene with various numbers of coupled layers is responsible for the variations in the density of states (DOS) pattern. For Ag NPs-FLGNs, the spatial variations in the DOS spectra can be correlated to the size effects of the Ag NPs over the FLGNs. The local density of states (LDOS) spectra originates from the quantized electronic structure of the Ag NPs–FLGs system.

Fabrication of PVA/CNC/Ag membrane by electrospinning method

In this study, the morphology, structure, and properties of three-component composite membrane including poly(vinylalcohol), cellulose nanocrystals, and nanosilver (PVA/CNC/Ag) fabricated by electrospinning method were presented. CNC, isolated from Nypa fruticans branches by a chemical method, was used as a membrane to synthesize Ag nanoparticles (CNC/Ag) by a simple heat treatment technique. The presence of Ag NPs on CNC and the antibacterial ability of CNC/Ag were verified by the disc diffusion method. The CNC/Ag material was then mixed with PVA and the electrospinning step was performed. The PVA/CNC/Ag membrane was characterized by methods such as X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FESEM), and differential scanning calorimetry (DSC). The FESEM results demonstrated that PVA/CNC/Ag had an irregular fiber morphology, rough surface, and fibers with an average diameter of about 70 nm, larger than both PVA and PVA/CNC. DSC analysis indicated that the presence of CNC/Ag had a significant effect on the thermal properties of the PVA/CNC/Ag material. These initial results showed that it was necessary to further investigate the fabricating parameters of the electrospinning process to optimize the properties of the PVA/CNC/Ag materials in order to afford membranes with suitable properties for wound dressing applications.

Multifunctional chitosan/gelatin@tannic acid cryogels decorated with in situ reduced silver nanoparticles for wound healing.

BackgroundMost traditional wound dressings only partially meet the needs of wound healing because of their single function. Patients usually suffer from the increasing cost of treatment and pain resulting from the frequent changing of wound dressings. Herein, we have developed a mutifunctional cryogel to promote bacterial infected wound healing based on a biocompatible polysaccharide.MethodsThe multifunctional cryogel is made up of a compositive scaffold of chitosan (CS), gelatin (Gel) and tannic acid (TA) and in situ formed silver nanoparticles (Ag NPs). A liver bleeding rat model was used to evaluate the dynamic hemostasis performance of the various cryogels. In order to evaluate the antibacterial properties of the prepared cryogels, gram-positive bacterium Staphylococcus aureus (S. aureus) and gram-negative bacterium Escherichia coli (E. coli) were cultured with the cryogels for 12 h. Meanwhile, S. aureus was introduced to cause bacterial infection in vivo. After treatment for 2 days, the exudates from wound sites were dipped for bacterial colony culture. Subsequently, the anti-inflammatory effect of the various cryogels was evaluated by western blotting and enzyme-linked immunosorbent assay. Finally, full-thickness skin defect models on the back of SD rats were established to assess the wound healing performances of the cryogels.ResultsDue to its porous structure, the multifunctional cryogel showed fast liver hemostasis. The introduced Ag NPs endowed the cryogel with an antibacterial efficiency of >99.9% against both S. aureus and E. coli. Benefited from the polyphenol groups of TA, the cryogel could inhibit nuclear factor-κB nuclear translocation and down-regulate inflammatory cytokines for an anti-inflammatory effect. Meanwhile, excessive reactive oxygen species could also be scavenged effectively. Despite the presence of Ag NPs, the cryogel did not show cytotoxicity and hemolysis. Moreover, in vivo experiments demonstrated that the biocompatible cryogel displayed effective bacterial disinfection and accelerated wound healing.ConclusionsThe multifunctional cryogel, with fast hemostasis, antibacterial and anti-inflammation properties and the ability to promote cell proliferation could be widely applied as a wound dressing for bacterial infected wound healing.

Introducing a Novel Chemotherapeutic Drug for the Treatment of Lung Adenocarcinoma: Silver Nanoparticles Green-formulated by Cinnamomum verum.

In this study we report the green synthesis of nontoxic, stable, and small size silver nanoparticle by Cinnamomum verum with reducing/capping ability without any toxic reducing agents. The in situ prepared AgNPs were characterized by advanced physicochemical techniques like FE-SEM, TEM, and UV-Vis study. It has been established that AgNPs have a spherical shape with a mean diameter from 10 to 45 nm. In the antioxidant test, the IC50 of AgNPs and BHT against DPPH free radicals were 191 and 242 µg/mL, respectively. In the cellular and molecular part of the recent study, the treated cells with AgNPs were assessed by MTT assay for 48 h about the cytotoxicity and anti-human lung adenocarcinoma properties on normal (HUVEC) and lung adenocarcinoma cell lines i.e. PC-14, LC-2/ad, and HLC-1. The IC50 of AgNPs were 259, 291, and 395 µg/mL against PC-14, LC-2/ad, and HLC-1 cell lines, respectively. The viability of malignant lung cell line reduced dose-dependently in the presence of AgNPs.