Functionalized Gold and Silver Bimetallic Nanoparticles Using Deinococcus radiodurans Protein Extract Mediate Degradation of Toxic Dye Malachite Green.

BACKGROUND: Biodegradation of toxic organic dye using nanomaterial-based microbial biocatalyst is an ecofriendly and promising technique. MATERIALS AND METHODS: Here, we have investigated the novel properties of functionalized Au-Ag bimetallic nanoparticles using extremophilic Deinococcus radiodurans proteins (Drp-Au-AgNPs) and their degradation efficiency on the toxic triphenylmethane dye malachite green (MG). RESULTS AND DISCUSSION: The prepared Drp-Au-AgNPs with an average particle size of 149.8 nm were capped by proteins through groups including hydroxyl and amide. Drp-Au-AgNPs demonstrated greater degradation ability (83.68%) of MG than D. radiodurans cells and monometallic AuNPs. The major degradation product was identified as 4-(dimethylamino) benzophenone, which is less toxic than MG. The degradation of MG was mainly attributed to the capping proteins on Drp-Au-AgNPs. The bimetallic NPs could be reused and maintained MG degradation ability (>64%) after 2 cycles. CONCLUSION: These results suggest that the easily prepared Drp-Au-AgNPs have potential applications as novel nanomedicine for MG detoxification, and nanomaterial for biotreatment of a toxic polyphenyl dye-containing wastewater.

In Situ Formation of Homogeneous Tellurium Nanodots in Paclitaxel-Loaded MgAl Layered Double Hydroxide Gated Mesoporous Silica Nanoparticles for Synergistic Chemo/PDT/PTT Trimode Combinatorial Therapy.

A folic acid (FA) functional drug delivery system (MT@L-PTX@FA) based on in situ formation of tellurium nanodots (Te NDs) in paclitaxel (PTX)-loaded MgAl layered double hydroxide (LDHs) gated mesoporous silica nanoparticles (MSNs) has been designed and fabricated for targeted chemo/PDT/PTT trimode combinatorial therapy. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), N2 adsorption-desorption, Fourier transform infrared (FT-IR) spectra, and UV-vis spectra were used to demonstrate the successful fabrication of MT@L-PTX@FA. In particular, the in situ generated Te NDs showed a homogeneous ultrasmall size. Reactive oxygen species (ROS) generation, photothermal effects, and photostability evaluations indicated that the in situ generated homogeneous Te NDs could serve as the phototherapeutic agent, converting the photon energy to ROS and heat under near-infrared (NIR) irradiation efficiently. The drug-release test revealed that MT@L-PTX@FA showed an apparent sustained release character in a pH-sensitive manner. In addition, cell imaging experiments demonstrated that MT@L-PTX@FA could selectively enter into cancer cells owing to the function of FA and release of PTX efficiently for chemotherapy for the reason that the low intracellular pH would dissolve MgAl LDHs to Mg2+ and Al3+. Cytotoxicity tests also indicated that MT@L-PTX@FA exhibited enhanced therapeutic effect in cancer cells under NIR irradiation, benefiting from the synergy based on targeted chemo/PDT/PTT trimode combinatorial therapy. The preliminary results reported here will shed new light on the future design and applications of nanosystems for synergistic combinatorial therapy.

Adsorption and leaching of novel fungicide pyraoxystrobin on soils by 14C tracing method.

Pyraoxystrobin, (E)-2-(2-((3-(4-chlorophenyl)-1-methyl-1H-pyrazole-5-yloxy)methyl)phenyl)-3-methoxyacrylate, is a newly developed strobilurin fungicide with high antifungal efficiency. It has high potential to enter soil environments that might subsequently impact surface and groundwater. Therefore, 14C-labeled pyraoxystrobin was used as a tracer to study the adsorption/desorption and migration behavior of this compound under laboratory conditions in three typical agricultural soils. The adsorption isotherms conformed with the Freundlich equation. Single factor analysis showed that organic matter content was the most important factor influencing the adsorption. The highest adsorption level was measured in soil with low pH and high organic carbon content. Once adsorbed, only 2.54 to 6.41% of the adsorbed compound could be desorbed. In addition, the mobility results from thin-layer chromatography and column leaching studies showed that it might be safe to use pyraoxystrobin as a fungicide without causing groundwater pollution from both runoff and leaching, which might be attributed to its strong hydrophobicity. High organic matter content enhanced pyraoxystrobin adsorption and desorption because of the rule of similarity (lipid solubility). In the column leaching study, 95.02% (minimum value) of the applied 14C remained within the upper 4.0-cm layer after 60 days.

Uptake and distribution characteristics of the novel fungicide pyraoxystrobin in cucumber plants.

The uptake and distribution characteristics of a novel fungicide, pyraoxystrobin, labeled with 14C on its pyrazol ring, were investigated in cucumber (Cucumis sativus) seedlings. Foliar applied pyraoxystrobin rapidly penetrated the treated leaf and reached a maximum uptake of 68% after 5 d. The translocation of absorbed 14C in cucumber seedlings was both acropetal and basipetal. However, over 74% of the absorbed 14C-pyraoxystrobin remained in the treated leaves. The order of its distribution in the plant was as follows: treated leaf > stalk above the treated leaf > leaves above the treated leaf > stalk below the treated leaf > leaves below the treated leaf > cotyledon > root. Seedlings grown in soils containing bound residues (BR) of pyraoxystrobin revealed that the BRs were not easily absorbed or translocated by the plant. Soil type had a large effect on root uptake, with the highest uptake among the three tested soils from red clay.

Adsorption of uranium by amidoximated chitosan-grafted polyacrylonitrile, using response surface methodology.

The amidoximated chitosan-grafted polyacrylonitrile (CTS-g-PAO) was prepared for the adsorption of uranium from water. The effects of pH, concentration of uranium and the solid-liquid ratio on the adsorption of uranium by CTS-g-PAO were optimized using Doehlert design of response surface methodology (RSM). The adsorption capacity and removal efficiency achieved 312.06 mg/g and 86.02%, respectively. The adsorption process attained equilibrium only in 120 min. More than 80% of the absorbed uranium could be desorbed by 0.1 mol/l HCl or EDTA-Na, and CTS-g-PAO could be reused at least 3 times. The CTS-g-PAO and U(VI) ions formed a chelate complex due to FTIR spectral analysis. The surface morphology of CTS-g-PAO was also investigated by SEM. The adsorption process was better described by Langmuir isotherm and pseudo second order kinetic model. Results obtained indicated that CTS-g-PAO was very promising in adsorption of uranium from water.

Fate of a novel strobilurin fungicide pyraoxystrobin in flooded soil.

Pyraoxystrobin, ((E)-2-(2-((3-(4-chlorophenyl)-1-methyl-1H-pyrazol-5-yloxy) methyl) phenyl)-3-methoxyacrylate) is a novel strobilurin fungicide with excellent and broad spectrum antifungal efficiency. Environmental behaviors of the new fungicide must be assessed to understand its potential risks to the environment. In this study, the extractable residues, bound residues and mineralization, as well as the dissipation rates of pyraoxystrobin were investigated in three flooded soils using a (14)C tracing technique. Results showed that pyraoxystrobin didn't undergo appreciable dissipation during the 100 day incubation period in some tested soils, with 70.01%, 28.58% and 83.85% of the parent compound remaining in the solonchak, cambisol and acrisol soils at the end of the experiment, respectively. Almost no (14)C-pyraoxystrobin was mineralized to (14)CO2 (<0.5%) over the experimental period. Organic matter had a dominating influence on the bound residues formation and the fractions of bound residues increased as the soil organic matter content increased. Less than 9% of the radioactivity was found in the aqueous phase, while the majority of extractable residues (>65.39%) were recovered in the organic extracts. This study aims to give a deep insight into the environmental behaviors of pyraoxystrobin and may be beneficial for the risk assessment of other analogous fungicides.

Dynamic characteristics of the novel strobilurin fungicide SYP-3343 in aerobic soils.

SYP-3343, (E)-2-(2-((3-(4-chlorophenyl)-1-methyl-1H-pyrazole-5-yloxy)methyl)phenyl)-3-methoxyacrylate, is a newly developed strobilurin fungicide. However, the environmental behavior and fate of SYP-3343 in soil have not been well-documented. In this study, ¹4C-labeled SYP-3343 was employed to investigate the dynamic characteristics in three typical soils under aerobic conditions. Radioactivity analysis after high-performance liquid chromatography (HPLC) showed that SYP-3343 degraded rapidly in the coastal soil with a half-life of 43.8 days. After incubation of 100 days, its extractable residues were greater than 76.0% and bound residues were less than 12.4%, indicating that SYP-3343 was not easy to accumulate in soils. The mineralization to ¹4CO2 reached 5.4% for acidic soil, 2.8% for neutral soil, and 1.7% for alkaline soil, suggesting that it was difficult to cleave the pyrazole ring completely. In addition, dynamic characteristics of SYP-3343 in sterile and non-sterile loamy soil showed that soil microbes affected SYP-3343 residue in soil and could accelerate the process of degradation and mineralization.

Chromatographic Zinc Isotope Separation by Chelating Exchange Resin.

Zinc isotope separations were studied by displacement chromatography using the chelating properties of malate, citrate and lactate exchange resin and EDTA as ligands. After each chromatographic operation, the heavier zinc isotopes were found to preferentially fractionated into the carboxylate complex solution phase. The separation coefficients (epsilon) for zinc isotope separation had the largest value and were obtained for the isotopic pairs (68)Zn/(64)Zn (7.16 x 10(-4)) and (66)Zn/(64)Zn (3.08 x 10(-4)), respectively, at 298 +/- 1 K. The separation coefficient per unit mass differences (epsilon/DeltaM) for the isotopic pair of (68)Zn/(64)Zn was found to range around 1.55 x 10(-4).

High enrichment of 15N by chromatographic chemical process.

Nitrogen isotope enrichment experiments were conducted to obtain highly enriched (15)N by ion-exchange process. (15)NH(4)Cl ((15)N=80%) as feeding materials were used to perform the chromatographic operation with two different flow rates and column diameters. Both separation coefficient (epsilon) and height equivalent to a theoretical plate (HETP) have same values in two run experiments. The value of HETP was more enlarged when high enrichment of (15)N was obtained in comparison with that of low enrichment. 99.756% (15)N and 13.63 g (15)N whose percentage was over 99.0% were successfully achieved by 25 m chromatographic migration with the flow rate and column diameter at 50 cm(3)/mL, 3.0 cm, respectively. High flow rate and large column diameter have advantages to the enrichment of (15)N by ion exchange process.

Chromatographic zinc isotope separation by phenol formaldehyde benzo crown resin.

New types of phenol formaldehyde resin having benzo crown as a functional group were synthesized and applied to zinc isotope chromatographic operation. Zinc adsorption and isotope separation capacities were dramatically improved by using phenol formaldehyde benzo-15-crown-5 resin. Zinc batch adsorption tests were performed by various dehydrated organic solvents. Separation coefficient, epsilon 8.1 x 10(-4) and height equivalent to a theoretical plate (HETP) 0.105 cm for the isotopic pair of 68Zn/64Zn in phenol formaldehyde benzo-15-crown-5 resin were obtained in the case of acetone as the solvent at 298+/-1K.