Oxidative stress, genotoxic effects, and other damages caused by chronic exposure to silver nanoparticles (Ag NPs) and zinc oxide nanoparticles (ZnO NPs), and their mixtures in zebrafish (Danio rerio).

This study assessed the oxidative stress impacts of Ag NPs and ZnO NPs and their mixtures in zebrafish (Danio rerio). Zebrafish were exposed to sublethal concentrations of each NP and a mixture for 28 days followed by a 28-day recovery period (without NP exposure) and measurements made on hepatic levels of antioxidant enzymes (CAT, SOD, and GPx), MDA levels, expression of the genes for the Hsp70 and Hsp90, and MT, blood biochemical parameters (total protein, globulin, albumin, AST, ALT, ALP, and LDH), and genotoxicity in erythrocytes (via measurement of micronuclei (MN) and nuclear (NA) abnormalities). There was a tendency for an increase in the variation in the responses of antioxidant defense systems and there were higher MDA levels with increasing exposure concentration of Ag NPs and with increasing exposure time. Total protein, globulin, and albumin decreased during the exposure period, especially on the days of 28. Moreover, levels of AST and LDH increased significantly in the NPs co-exposure treatments, while levels of ALT and ALP significantly decreased. The highest expression levels for these genes occurred on day 14 and in the NPs co-exposure treatments. For exposure to both NPs individually and as a mixture, the frequency of MN and other NA were significantly increased (p < 0.05). During the recovery periods, most of the effects seen were reduced, most notably in the individual NPs treatments. The overall results suggest that the toxic effects of Ag NPs and ZnO NPs in combination significantly increase their toxicity in zebrafish.

Toxicity of Silver Nanoparticles in the Presence of Zinc Oxide Nanoparticles Differs for Acute and Chronic Exposures in Zebrafish.

We assessed the acute toxicity effects (96 h) of silver nanoparticles (Ag NPs) and zinc oxide nanoparticles (ZnO NPs) and chronic (28 d) exposure to Ag NPs, including in combination with ZnO NPs. In the chronic studies, we further assessed the toxicokinetics and bioaccumulation of Ag and the resulting histopathological effects in the gill, intestine, and liver of zebrafish. Co-exposures with ZnO NPs reduced the toxicity of Ag NPs for acute (lethality) but enhanced the toxicity effects (tissue histopathology) for chronic exposures. The histological lesions for both NPs exposures in the gill included necrosis and fusion of lamellae, for the intestine necrosis and degeneration, and in the liver, mainly necrosis. The severity of the histological lesions induced by the Ag NPs was related to the amount of accumulated Ag in the zebrafish organs. The Ag accumulation in different organs was higher in the presence of ZnO NPs in the order of the gill > intestine > liver. Depuration kinetics illustrated the lowest half-life for Ag occurred in the gill and for the combined exposure of Ag with ZnO NPs. Our findings illustrate that in addition to tissue, time, and exposure concentration dependencies, the Ag NPs toxicity can also be influenced by the co-exposure to other NPs (here ZnO NPs), emphasizing the need for more combination exposure effects studies for NPs to more fully understand their potential environmental health risks.

Biosynthesis of NiFe2 O4 @Ag Nanocomposite and Assessment of Its Effect on Expression of norA Gene in Staphylococcus aureus.

Activity of norA efflux pump has been known as a resistance mechanism to antibiotics like ciprofloxacin in Staphylococcus aureus. This study was carried out to assess the effect of biosynthesized NiFe2 O4 @Ag nanocomposite on expression of norA gene in Staphylococcus aureus. In this experimental study, 30 clinical samples were collected from patients hospitalized at different hospitals in Guilan Province, Iran. Then, clinical isolates of S. aureus were identified by standard microbiological tests. Antimicrobial susceptibility tests of clinical and standard strains of S. aureus were done by disk diffusion method according to CLSI guideline. Fourier transform infrared spectroscopy (FT-IR) was used to analyze the various functional groups present in the biosynthesized NiFe2 O4 @Ag nanocomposite. This analysis confirmed the formation of alga proteins coated on magnetite nanocomposite. X-ray diffraction (XRD) verified the crystalline structure of NiFe2 O4 @Ag and the deposition of silver on the surface of NiFe2 O4 . Energy dispersive X-ray mapping (EDX-map) analysis confirmed the existence of Ag, Ni, Fe and O in the final product. Scanning electron microscopy (SEM) confirmed that the nanocomposites were spherical in shape and Transmission electron microscopy (TEM) results revealed that the NiFe2 O4 @Ag had the particle size about 100 nm. Antibacterial activity of NiFe2 O4 @Ag alone and combined with ciprofloxacin was evaluated using the disk assay method, and minimum inhibitory concentration (MIC) by broth dilution method. Afterwards, the expression of norA efflux pump gene with and without of NiFe2 O4 @Ag nanocomposite and ciprofloxacin was evaluated by Real-Time PCR. Real-Time PCR results demonstrated that the expression of norA gene in the strains exposed to both NiFe2 O4 @Ag nanocomposite (1/4 MIC) and ciprofloxacin (1/8 MIC) significantly reduced in comparison to untreated strains. This study reveals that, when NiFe2 O4 @Ag nanocomposite is combined with ciprofloxacin, the inhibitory effect of ciprofloxacin increases against growth of S. aureus. Therefore, NiFe2 O4 @Ag nanocomposite can be considered as an effective factor to decrease the growth of S. aureus along with ciprofloxacin.

Synthesis of Cobalt Hydroxide Nano-flakes Functionalized with Glutamic Acid and Conjugated with Thiosemicarbazide for Anticancer Activities Against Human Breast Cancer Cells.

In recent years, researchers were attracted to nanomaterials components for their potential role in cancer treatment. This study aimed to develop a novel and biocompatible cobalt hydroxide (Co(OH)2) nano-flakes that is functionalized by glutamic acid (Glu) and conjugated to thiosemicarbazide (TSC) for anticancer activities against human breast cancer MCF-7 cells. Physico-chemical properties of the Co(OH)2@Glu-TSC nanomaterial are characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive X-ray (EDX) analysis, and Fourier-transform infrared (FT-IR) spectroscopy. MTT assay, flow cytometry, and caspase-3 activity analysis used for evaluating anticancer properties of the Co(OH)2@Glu-TSC nanomaterial. The MTT assay result showed cellular uptake of Co(OH)2@Glu-TSC and cell viability loss in a concentration-dependent. Results of flow cytometry and caspase-3 activity analysis indicated the stimulation of apoptosis through an increase in Caspase-3 and nucleus fragmentation. In general, our findings indicate the anticancer activities of Co(OH)2@Glu-TSC nanomaterial and so it can be considered as a new treatment for breast cancer. However, further in vivo studies are required to evaluate the accumulation of Co(OH)2@Glu-TSC nanomaterial in healthy organs, such as the liver, kidneys, brain, and testes, and potential toxic effects.

A novel bioactive nanoparticle synthesized by conjugation of 3-chloropropyl trimethoxy silane functionalized Fe3O4 and 1-((3-(4-chlorophenyl)-1-phenyl-1H-pyrazol-4-yl)methylene)-2-(4-phenylthiazol-2-yl) hydrazine: assessment on anti-cancer against gastric AGS cancer cells.

Gastric cancer is one of the common types of cancer around the world which has few therapeutic options. Nitrogen heterocyclic derivatives such as thiazoles are used as the basis for the progression of the drugs. The objective of this study was to synthesize the 1-((3-(4-chlorophenyl)-1-phenyl-1H-pyrazol-4-yl) methylene)-2-(4-phenylthiazol-2-yl) hydrazine (TP) conjugating with (3-Chloropropyl) trimethoxysilane (CPTMOS)-coated Fe3O4 nanoparticles (NPs) for anti-cancer activities against gastric AGS cancer cell line. The synthesized Fe3O4@CPTMOS/TP NPs were characterized by FT-IR, XRD, EDX, SEM, TEM and Zeta potential analyses. To evaluate the toxicity of the above compound after AGS cell culture in RPMI1640 medium, the cells were treated at different concentrations for 24 h. The viability of the cells was investigated by MTT assay. Moreover, apoptosis induced by Fe3O4@CPTMOS/TP NPs was assessed by Hoechst 33432 staining, oxygen activity specification evaluation, caspase-3 activity assay, cell cycle analysis and annexin V/PI staining followed by flow cytometry analysis. The IC50 value in AGS cells was estimated to be 95.65 µg/ml. The flow cytometry results of Fe3O4@CPTMOS/TP NPs revealed a large number of cells in the apoptotic regions compared to the control cells and the cells treated with TP. In addition, the amount of ROS production and caspase-3 activity increased in the treated cells with Fe3O4@CPTMOS/TP NPs. The percentage of inhibited cancer cells in the G0/G1 phase increased under the treatment in the binding state to the nonionic iron oxide nanoparticles. Overall, this study showed that Fe3O4@CPTMOS/TP NP had effect on induction of apoptosis and inhibiting the growth of AGS cancer cells. Thus, Fe3O4@CPTMOS/TP NP can be considered as a new anti-cancer candid for next phase of studies on mouse models.

Immobilized VO-Schiff Base Complex on Modified Graphene Oxide Nanosheets as an Efficient and Recyclable Heterogeneous Catalyst in Deep Desulfurization of Model Oil.

New heterogeneous catalyst was synthesized via covalent anchoring of oxovanadium(IV) complex of 5,5?-dibromobis(salicyledene)diethylenetriamine (VO[5-Br(Saldien)]) on the surface of chloro-modified graphene oxide (GO@CTS). The structure of the catalyst was investigated using different characterization techniques such as XRD, SEM, EDX, FT-IR, TG, DTA and ICP-AES analyses. The synthesized heterogeneous oxovanadium(IV) was an efficient catalyst for high yield and selective oxidation desulfurization (ODS) of dibenzothiophene (DBT) as a model oil using H2O2 as oxidant and formic acid as a promoter. The effects of the catalyst mass, reaction temperature and time, formic acid/H2O2 ratio and molar ratio of H2O2 to the total amount of sulfur (O/S) on oxidation desulfurization activity were investigated. Moreover, the prepared catalyst can be easily separated from the reaction mixture and reused six times without a significant loss of catalytic activity and selectivity.

Novel pyridinecarboxaldehyde thiosemicarbazone conjugated magnetite nanoparticulates (MNPs) promote apoptosis in human lung cancer A549 cells.

The present study highlights the apoptotic activity of magnetic Fe3O4 nanoparticulates functionalized by glutamic acid and 2-pyridinecarboxaldehyde thiosemicarbazone (PTSC) toward human lung epithelial carcinoma A549 cell line. To this aim, the Fe3O4 nanoparticulates were prepared using co-precipitation method. Then, the glutamic acid and Fe3O4 nanoparticulates were conjugated to each other. The product was further functionalized with bio-reactive PTSC moiety. In addition, the synthesized Fe3O4@Glu/PTSC nanoparticulates were characterized by physico-chemical techniques including scanning electron microscope (SEM), energy dispersive X-ray (EDX), X-ray diffraction (XRD), Fourier-transform infrared (FT-IR) spectroscopy and zeta potential analysis. The effects of in vitro cell viability in Fe3O4@Glu/PTSC nanoparticulate indicated the anti-proliferative properties in a dose-dependent manner (IC50 = 135.6 µM/mL). The high selectivity for tumor cells and far below of activity in HEK293 non-tumorigenic cells is considered as an important feature for this complex (SI, 3.48). Based on the results, PTSC failed to reveal any activity against A549 cells alone. However, Fe3O4 nanoparticulates had some effects in inhibiting the growth of lung cancer cell. Furthermore, Bax and Bcl-2 gene expressions were quantified by real-time PCR method. The expression of Bax increased 1.62-fold, while the expression of Bcl-2 decreased 0.76-fold at 135.6 µM/mL concentration of Fe3O4@Glu/PTSC compared to untreated A549 cells. Furthermore, the Fe3O4@Glu/PTSC nanoparticulate-inducing apoptosis properties were evaluated by Hoechst 33258 staining, Caspase-3 activation assay and Annexin V/propidium iodide staining. The results of the present study suggest that Fe3O4@Glu/PTSC nanoparticulates exhibit effective anti-cancer activity against lung cancer cells.

Fe3O4/Ag nanocomposite biosynthesised using Spirulina platensis extract and its enhanced anticancer efficiency.

In this work, the authors investigated the apoptotic activities of Fe3O4/Ag nanocomposite biosynthesised by Spirulina platensis extract against MCF-7 (human breast cancer cells). The physico-chemical properties of prepared Fe3O4/Ag nanocomposite were studied by different spectroscopic methods. To evaluate the in vitro cytotoxic effect, MCF-7 cells were treated with different concentrations of Fe3O4/Ag nanocomposite and examined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) assay. Moreover, apoptotic effects were also studied by Hoechst 33258 staining, caspase 3 activation assays, and annexin V-fluorescein isothiocyanate (FITC) and propidium iodide staining. Microscopic observations of Fe3O4/Ag nanocomposites indicated approximately spherical shape and small particles in the size range of about 30-50 nm. The MTT assay result revealed that the Fe3O4/Ag nanocomposite causes a dose-dependent cell proliferation reduction in MCF-7 cells (IC50 = 135 µg/ml). Regarding to the Annexin V/PI staining result, the increase percentage of apoptotic cells (28.09%) was detected as compared to untreated cells. According to the caspase assay, Fe3O4/Ag nanocomposite enhances caspase 3 level. Furthermore, in vitro anti-cancer activity of the nanocomposite was performed by Hoechst 33258 staining method. The proposed data suggest that Fe3O4/Ag nanocomposite may be an effective agent for the inhibition of breast cancer cells at in vitro level.

Highly efficient removal of surfactant from industrial effluents using flaxseed mucilage in coagulation/photo-Fenton oxidation process.

In this study, flaxseed mucilage (FSM) has been used as a green coagulant in the pretreatment stage of a combined process for the removal of an anionic surfactant, sodium dodecyl sulfate (SDS). In the post-treatment stage, heterogeneous photo-Fenton-like oxidation using MnFe2O4 nanocatalyst was applied to remove the remained SDS. Using response surface methodological approach, optimum condition in the coagulation process was obtained at pH 7.0, FSM dose of 100 mg L-1 and 30 min. In the photo-Fenton oxidation process, complete SDS removal was achieved using 76 mg of the nanocatalyst, 1.07 mL of H2O2 at 17 min. Application of the combined process on the real wastewater samples indicates that the proposed method can be used effectively for the treatment of industrial effluents containing surfactants.

Enzyme mimetic activities of spinel substituted nanoferrites (MFe2O4): A review of synthesis, mechanism and potential applications.

Recently, the intrinsic enzyme-like activities of some nanoscale materials known as "nanozymes" have become a growing area of interest. Nanosized spinel substituted ferrites (SFs) with general formula of MFe2O4, where M represents a transition metal, are among a group of magnetic nanomaterials attracting researchers' enormous attention because of their excellent catalytic performance, biomedical applications and capability for environmental remediation. Due to their unique nanoscale physical-chemical properties, they have been used to mimic the catalytic activity of natural enzymes such as peroxidases, oxidases and catalases. In addition, various nanocomposite materials based on SFs have been introduced as novel artificial enzymes. This review mainly highlights the synthetic approaches for newly developed SF-nanozymes and also the structural/experimental factors that are effective on the kinetics and catalytic mechanisms of enzyme-like reactions. SF-nanozymes have been found potentially capable of being applied in various fields such as enzyme-free immunoassays and biosensors for colorimetric detection of biological molecules. Therefore, the application of SF nanoparticles, as efficient enzyme mimetics have been detailed discussed.

Biosynthesis of Fe3O4@Ag Nanocomposite and Evaluation of Its Performance on Expression of norA and norB Efflux Pump Genes in Ciprofloxacin-Resistant Staphylococcus aureus.

At present, the universal health problem with Staphylococcus aureus is the emergence of multidrug-resistant strains due to the overuse of antibiotics. Drug extrusion through efflux pumps is one of the bacterial mechanisms to neutralize the bactericidal effect of antibiotics. The antibacterial activity of silver nanoparticle as well as Fe3O4 nanoparticle had been previously studied and widely described. Today, the development of green methods for nanomaterial synthesis is an important aspect of research in the field of nanotechnology. Here, we report the biosynthesis and characterization of Fe3O4@Ag nanocomposite by Spirulina platensis cyanobacterium and it impacts on the expression of efflux pump genes in ciprofloxacin-resistant S. aureus (CRSA). The physical properties of biosynthesized nanocomposite measured and confirmed by ultraviolet-visible spectroscopy, Fourier-transform infrared spectroscopy, X-ray diffraction, energy-dispersive X-ray spectroscopy, and scanning and transmission electron microscopy. The minimum inhibitory concentration (MIC) of ciprofloxacin in CRSA strains was determined in the presence of Fe3O4@Ag nanoparticles by broth microdilution method. The effect of Fe3O4@Ag nanocomposite on the expression of norA and norB genes was evaluated by real-time PCR. The physical analysis confirmed well-dispersed, highly stable, and mostly spherical Fe3O4/Ag NPs with the average size of 30-68 nm. The results of antibacterial tests showed the synergistic effects of nanocomposite and antibiotics in MIC reduction. Additionally, in the presence of Fe3O4@Ag nanocomposite, the expression of norA and norB genes was decreased more than twofold compared to control. In conclusion, the Fe3O4/Ag nanocomposite can use as an effective inhibitor of antibiotic resistance in medicine.

The use of a cis-dioxomolybdenum(VI) dinuclear complex with quadradentate 1,4-benzenediylbis(benzyldithiocarbamate)(2-) as model compound for the active site of oxo transfer molybdoenzymes: reactivity, kinetics, and catalysis.

Dinuclear cis-dioxomolybdenum(VI) complex [{MoO(2)(Bz(2)Benzenediyldtc)}(2)] coordinated by a quadradentate dithiocarbamate (Bz(2)Benzenediyldtc(2-)=1,4-benzenediylbis(benzyldithiocarbamate)(2-)) has been prepared and characterized by elemental analysis, (13)C NMR, IR and UV-vis spectroscopy. The kinetics of the oxygen atom transfer between [{MoO(2)(Bz(2)Benzenediyldtc)}(2)] and PPh(3) was studied spectrophotometrically in CH(2)Cl(2) medium at 520 nm and four different temperatures, 288, 293, 298 and 303 K, respectively. The reaction follows second order kinetics with the rate constant k=0.163(2)M(-1)S(-1) and its increasingly strong absorption at 520 nm clearly indicate the formation of a µ-oxo molybdenum(V) species as a product. Despite the steric restrictions imposed by the ligand structure to prevent the formation of Mo(V) species, experimental evidence confirms its interference during the process. The product can then be formulated as [MoO(2)(Bz(2)Benzenediyldtc)(2)Mo(2)O(3)(Bz(2)Benzenediyldtc)(2)MoO(2)] which has one µ-oxomolybdenum(V) moiety. An Eyring plot allows the activation parameters ΔH(‡)=64.2(1) kJ mol(-1) and ΔS(‡)=-45.1(6) J K(-1) mol(-1) to be determined from the temperature dependence of the rate constant, suggesting an associative transition state for the oxo transfer reaction. Catalytic oxygen atom transfer reaction from DMSO to PPh(3) was also followed by monitoring the chemical shift changes in (31)P NMR spectroscopy. The substrate oxidation process follows a well-defined catalytic cycle capable of 100% conversion for the reaction of PPh(3) and DMSO without intervention of Mo(V) formation during about 36 h.