Catalytically enhanced direct degradation of nitro-based antibacterial agents using dielectric barrier discharge cold atmospheric pressure plasma and rhenium nanoparticles.

The common utilization of antimicrobial agents in medicine and veterinary creates serious problems with multidrug resistance spreading among pathogens. Bearing this in mind, wastewaters have to be completely purified from antimicrobial agents. In this context, a dielectric barrier discharge cold atmospheric pressure plasma (DBD-CAPP) system was used in the present study as a multifunctional tool for the deactivation of nitro-based pharmacuticals such as furazolidone (FRz) and chloramphenicol (ChRP) in solutions. A direct approach was applied to this by treating solutions of the studied drugs by DBD-CAPP in the presence of the ReO4- ions. It was found that Reactive Oxygen Species (ROS) and Reactive Nitrogen Species (RNS), generated in the DBD-CAPP-treated liquid, played a dual role in the process. On the one hand, ROS and RNS led to the direct degradation of FRz and ChRP, and on the other hand, they enabled the production of Re nanoparticles (ReNPs). The produced in this manner ReNPs consisted of catalytically active Re+4, Re+6, and Re+7 species which allowed the reduction of -NO2 groups contained in the FRz and ChRP. Unlike the DBD-CAPP, the catalytically enhanced DBD-CAPP led to almost FRz and ChRP removals from studied solutions. The catalytic boost was particularly highlighted when catalyst/DBD-CAPP was operated in the synthetic waste matrix. Re-active sites in this scenario led to the facilitated deactivation of antibiotics, achieving significantly higher FRz and ChRP removals than DBD-CAPP on its own.

New Palladium - ZrO2 Nano-Architectures from Thermal Transformation of UiO-66-NH2 for Carbonylative Suzuki and Hydrogenation Reactions.

The new nanocomposites, Pd/C/ZrO2 , PdO/ZrO2, and Pd/PdO/ZrO2 , were prepared by thermal conversion of Pd@UiO-66-Zr-NH2 (MOF) in nitrogen or air atmosphere. The presence of Pd nanoparticles, uniformly distributed on the ZrO2 or C/ZrO2 matrix, was evidenced by transmission electron microscopy, scanning electron microscopy (SEM), Raman and X-ray Photoelectron Spectroscopy (XPS) methods. All pyrolysed composites retained the shape of the MOF template. They catalyze carbonylative Suzuki coupling under 1 atm CO with an efficiency significantly higher than the original Pd@UiO-66-Zr-NH2 . The most active PdO/ZrO2 composite, formed benzophenone with TOF up to 1600 h-1 , while by using Pd@UiO-66-Zr-NH2 , much lower TOF values, 51-95 h-1 , were achieved. After the reaction, PdO/ZrO2 was recovered with the same composition and catalytic activity. Very good results were also obtained in the transfer hydrogenation of benzophenones to alcohols with Pd/C/ZrO2 and PdO/ZrO2 catalysts under microwave irradiation.

Fixed-Bed Modification of Zeolitic Tuffs and Their Application for Cr(VI) Removal.

Natural clinoptilolite tuff (CL) and chabazite-clinoptilolite tuff (CH) were modified in fixed-bed column by immobilization of hexadecyltrimethylammonium bromide (HDTMA-Br), then investigated as a sorbent for inorganic anions of Cr(VI). The proposed modification technique combined with surfactant solution batching allows minimizing the surfactant loses through foaming and crystallization and creation of stable organic coverage. The HDTMA loading depended on the mineral composition of the zeolitic tuff, the topology of its external surface, and process conditions. The maximum surface coverage was obtained by gradually dosing surfactant solution in the smallest volume of batches and corresponded up to 100% and 182% of external cation exchange capacity (ECEC) for mono and double layer coverage, respectively. In case of mono layer coverage, modification proceeds until the exhaustion of surfactant in supply solution, while in the double layer one, until equilibrium of HDTMA concentration in both zeolitic and liquid phases was established. The efficiency of Cr(VI) uptake by prepared surface modified zeolites (SMZs) increased with increasing of HDTMA loading. In the case of mono layer SMZs, the capacities of CH-HDTMA and CL-HDTMA were 10.3 and 5.4 mg/g, respectively, while in the case of double layer SMZs, the amount of Cr uptake on CH-HDTMA and CL-HDTMA were 16.8 and 15 mg/g, respectively. Ion exchange is the predominant mechanism of Cr(VI) sorption but it takes place only if modification resulted in at least partial double layer coverage. The XPS analysis reveals Cr(VI) reduction to a less-toxic Cr(III) by the electron donating N-containing groups and by reaction with Fe+2 ions on the zeolite external surface.

Cytotoxicity Study of UV-Laser-Irradiated PLLA Surfaces Subjected to Bio-Ceramisation: A New Way towards Implant Surface Modification.

In this research we subjected samples of poly(L-lactide) (PLLA) extruded film to ultraviolet (193 nm ArF excimer laser) radiation below the ablation threshold. The modified film was immersed in Simulated Body Fluid (SBF) at 37 °C for 1 day or 7 days to obtain a layer of apatite ceramic (CaP) coating on the modified PLLA surface. The samples were characterized by means of optical profilometry, which indicated an increase in average roughness (Ra) from 25 nm for the unmodified PLLA to over 580 nm for irradiated PLLA incubated in SBF for 1 day. At the same time, the water contact angle decreased from 78° for neat PLLA to 35° for irradiated PLLA incubated in SBF, which suggests its higher hydrophilicity. The obtained materials were investigated by means of cell response fibroblasts (3T3) and macrophage-like cells (RAW 264.7). Properties of the obtained composites were compared to the unmodified PLLA film as well as to the UV-laser irradiated PLLA. The activation of the PLLA surface by laser irradiation led to a distinct increase in cytotoxicity, while the treatment with SBF and the deposition of apatite ceramic had only a limited preventive effect on this harmful impact and depended on the cell type. Fibroblasts were found to have good tolerance for the irradiated and ceramic-covered PLLA, but macrophages seem to interact with the substrate leading to the release of cytotoxic products.

Study of Mono- and Bimetallic Fe and Mn Oxide-Supported Clinoptilolite for Improved Pb(II) Removal.

A cost-effective, iron- and manganese-oxide-supported clinoptilolite-based rock was prepared. Based on its nanoporous structure, it worked as a nanoreactor, thereby providing enhanced functionalities. The mono- and bimetallic Fe- and Mn-oxide-supported clinoptilolite was thoroughly characterized with thermoanalytical FT-IR, XRD, SEM, and XPS spectroscopy. All the spectral procedures that were used confirmed the occurrence of a new MnO2 phase (predominantly birnessite), including mostly amorphous iron oxi(hydr)oxide (FeO(OH)) species on the surface of the above-synthesized adsorbents. The synthesized products validated a considerably higher adsorption capacity toward Pb(II) pollutants compared to the natural clinoptilolite. The following order of a(max) toward Pb(II) was found: MnOx-zeolite (202.1 mg/g) > FeO(OH)-MnOx-zeolite (101.3 mg/g) > FeO(OH)-zeolite (80 mg/g) > natural zeolite (54.9 mg/g). The adsorption equilibrium data were analyzed by the two-parameter empirical isotherm models Langmuir, Freundlich, and BET as well as the three-parameter Redlich-Peterson isotherm.

Immobilization of Rh(I) precursor in a porphyrin metal-organic framework - turning on the catalytic activity.

Two model porphyrin metal-organic frameworks were used for the incorporation of Rh(i) species by a post-synthetic metallation under mild conditions. As a result, new rhodium MOFs (Rh/MOFs), Rh/PCN-222 and Rh/NU-1102, were synthesized and structurally characterized. To illustrate the potential of this catalytic platform, we use Rh/MOFs as phosphine-free heterogeneous catalysts in the hydrogenation of unsaturated hydrocarbons under mild reaction conditions (30 °C and 1 atm H2). We found that for our Rh/MOFs an activation step is required during the first run of the catalytic process. The presence of Rh-CO moieties allowed us to monitor the activation pathway of the catalyst under a H2 atmosphere, by in situ Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS). After activation, the catalyst remains highly active during the subsequent catalytic cycles. This simple post-synthetic modification approach presents new possibilities for the utilization of Rh-based catalytic systems with robust porphyrin-based MOFs as supports.

Titanium anodizing in a choline dihydrogencitrate salt-oxalic acid deep eutectic solvent: a step towards green chemistry in surface finishing of titanium and its alloys.

Deep Eutectic Solvents (DESs) are "green" competitors for some conventional plating baths and electrolytes used for surface modification. Their use allows a material to be obtained with a structure different from that observed in conventional plating or finishing technologies. In this work the titanium anodizing process was investigated in a bath based on a choline dihydrogencitrate salt and oxalic acid (1 : 1 molar ratio) green solvent. Titanium anodized at the lowest voltage applied (10 V) was a deep yellow color, which turned to deep blue at 30 V. The surface morphology and topography of titanium, both anodized and untreated, were monitored by optical, scanning electron (SEM and HR-SEM) and atomic force (AFM) microscopy. Anodizing at 10 V produced a fine granular morphology of the oxide layer, while anodizing at 30 V led to the formation of a probably thicker and quite uneven oxide layer, characterized by a distinct and coarse granular morphology. The average size of the micro-nodules was higher than those at 10 V and porous structures have been also identified. According to X-ray photoelectron spectroscopy (XPS) the stoichiometric TiO2, regardless of the applied voltage during anodizing, was practically the only component of the oxide layer produced on titanium in the DES bath. At 10 V, the oxide layer was thicker (>10 nm) than the natural Ti passive layer (approx. 2.2 nm), which, apart from TiO2, also contained oxides of titanium at lower oxidation states, i.e. +2 and +3. Moreover, the XPS technique was supported by electrochemical impedance spectroscopy (EIS), especially in the context of the structure of the oxide layer and its interaction with a corrosive environment. The corrosion resistance of anodized titanium was assessed in 0.05 mol dm-3 solution of NaCl by the linear polarization resistance (LPR) technique and polarization curves. During interpretation of the impedance spectra, the layers produced by the anodizing process were described using the two-layer model. It was assumed that the inner layer formed directly on the surface of metallic titanium was responsible for the barrier properties (resistance of 2.8 MΩ cm2). The porous outer layer formed on it has a much lower corrosion resistance, i.e. 800-1300 Ω cm2.

Sulfonated hydroxyaluminum phthalocyanine-biogenic Au/Ag alloy nanoparticles mixtures for effective photo-eradication of Candida albicans.

In response to the increasingly widespread resistance of fungi to traditional treatment, we have reported successful photodynamic inactivation of Candida albicans planktonic cells using di-(AlPcS2) and trisulfonated (AlPcS3) hydroxyaluminum phthalocyanines in combination with Au/Ag alloy nanoparticles synthesized by the cell-free filtrate of Trichoderma koningii. These nanostructures with Au:Ag molar ratios 2:1, 1:1 and 1:2 have individual plasmonic band at 513-515 nm, 505-509 nm and 486-489 nm, respectively. XPS analysis of the ratio of gold to silver on the surface of these alloys indicated that Au and Ag formed a bimetallic system, wherein Au was coated with Ag. The XRD pattern revealed the angles at 38.2, 44.5, 64.9 and 78.0°. TEM analysis indicated that the average diameter of the synthesized alloys was 9 ± 3 nm, 8 ± 3 nm and 16 ± 3 nm for structures with Au:Ag molar ratios 1:1, 1:2 and 2:1, respectively. The FTIR band absorption, SEM-EDS analysis and basic elemental composition obtained by XPS confirmed that these nanostructures are stabilized by protein(s). Diode laser with the peak-power wavelength ʎ = 650 nm (output power of 40 mW; power density of 105 mW cm-2) was used as a light source. The mixture of AlPcS2+Au/Ag-NPs (Au:Ag = 2:1) can be considered as an effective photosensitizer, because eradication of C. albicans, as required by the American Society of Microbiology (99.9 %), was achieved at a low dose of light of 31.5 J cm-2. It was postulated that this low dose of light applied to the photo-induced fungicidal effect may be painless for potential patients.

Investigation of amino-grafted TiO2/reduced graphene oxide hybrids as a novel photocatalyst used for decomposition of selected organic dyes.

A novel type of photocatalyst - hybrids of amino-grafted titania and reduced graphene oxide - was synthesized by a hydrothermal method. The hybrids were comprehensively analyzed, including determination of their morphology (TEM), porous structure parameters (low-temperature N2 sorption) and crystalline structure (XRD). Additionally, to confirm the effective bonding of the amino-grafted titania and reduced graphene oxide, Raman and X-ray photoelectron spectroscopy (XPS) were used, in addition to elemental analysis. The key stage of the research was an evaluation of the photocatalytic activity of the synthesized hybrid photocatalysts with respect to the decomposition of C.I. Basic Blue 9 and C.I. Basic Red 1 dyes. It was found that the amino-grafted titania/reduced graphene oxide hybrids exhibited better photocatalytic activity in the degradation of C.I. Basic Blue 9 and C.I. Basic Red 1 than amino-grafted TiO2 alone. The high efficiency of dye decomposition can be attributed to the higher BET surface area and good separation of photogenerated electrons and holes offered by graphene oxide.

Enhancement of photo-bactericidal effect of tetrasulfonated hydroxyaluminum phthalocyanine on Pseudomonas aeruginosa.

At the present time, photodynamic inactivation (PDI) is receiving considerable interest for its potential as an antimicrobial therapy. The results of our study indicate that enhancement of the phototoxic effect on Pseudomonas aeruginosa can be achieved by combination of tetrasulfonated hydroxyaluminum phthalocyanine (AlPcS4) and bimetallic gold/silver nanoparticles (Au/Ag-NPs) synthesized by the cell-free filtrate of Aureobasidium pullulans. The bimetallic nanoparticles were characterized by a number of techniques including UV-vis, XPS, TEM, and SEM-EDS to be 14 ± 3 nm spherical particles coated with proteins. The effect of diode lasers with the peak-power wavelength ʎ = 650 nm (output power of 10 and 40 mW; radiation intensity of 26 and 105 mW/cm2) in combination with the AlPcS4 and the bimetallic nanoparticles mixture on the viability of P. aeruginosa rods was shown. Particularly high efficiency of killing bacterial cells was obtained for the light intensity of 105 mW/cm2, after 20, 30, and 40 min of irradiation corresponding to 126, 189, and 252 J/cm2 energy fluences. For AlPcS4+Au/Ag-NPs treatment, the viable count reduction were equal to 99.90, 99.96, and 99.975%, respectively. These results were significantly better than those accomplished for irradiated separated assays of AlPcS4 and Au/Ag-NPs.

Biomineralization of gold by Mucor plumbeus: The progress in understanding the mechanism of nanoparticles' formation.

This contribution describes the deposition of gold nanoparticles by microbial reduction of Au(III) ions using the mycelium of Mucor plumbeus. Biosorption as the major mechanism of Au(III) ions binding by the fungal cells and the reduction of them to the form of Au(0) on/in the cell wall, followed by the transportation of the synthesized gold nanoparticles to the cytoplasm, is postulated. The probable mechanism behind the reduction of Au(III) ions is discussed, leading to the conclusion that this process is nonenzymatic one. Chitosan of the fungal cell wall is most likely to be the major molecule involved in biomineralization of gold by the mycelium of M. plumbeus. Separation of gold nanoparticles from the cells has been carried out by the ultrasonic disintegration and the obtained nanostructures were characterized by UV-vis spectroscopy and transmission electron micrograph analysis. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 33:1381-1392, 2017.

Location of Varying Hydrophobicity Zinc(II) Phthalocyanine-Type Photosensitizers in Methoxy Poly(ethylene oxide) and Poly(l-lactide) Block Copolymer Micelles Using 1H NMR and XPS Techniques.

Hydrophobic zinc(II) phthalocyanine-type derivatives, solubilized in polymeric micelles (PMs), provide a befitting group of so-called nanophotosensitizers, suitable for a variety of photodynamic therapy (PDT) protocols. The factors that influence the success of such products in PDT are the location of the active cargo in the PMs and the nanocarrier-enhanced ability to safely interact with biological systems and fulfill their therapeutic functions. Therefore, the aim of this work was to determine the solubilization loci of three phthalocyanines of varying hydrophobicity, i.e., zinc(II) phthalocyanine (ZnPc), along with its tetrasulfonic acid (ZnPc-sulfo4) and perfluorinated (ZnPcF16) derivatives, loaded in polymeric micelles of methoxy poly(ethylene oxide)-b-poly(l-lactide) (mPEG-b-PLLA), by means of 1H nuclear magnetic resonance (NMR) and X-ray photoelectron spectroscopy (XPS) combined with ion sputtering. Furthermore, the microenvironment influence upon the chemical and physical status of the solubilized cargo in PMs, expressed by photobleaching and reactive oxygen species (ROS) generation comparing to the same properties of native cargoes in solution, was also evaluated and discussed in regards to the probing location data. The studied phthalocyanine-loaded PMs exhibited good physical stability, high drug-loading efficiency, and a size of less than ca. 150 nm with low polydispersity indices. The formation of polymeric micelles and the solubilization locus were investigated by 1H NMR and XPS. ZnPc localized within the PM core, whereas both ZnPcF16 and ZnPc-sulfo4 - in the corona of PMs. We proved that the cargo locus is crucial for the photochemical properties of the studied phthalocyanines; the increase in photostability and ability to generate ROS in micellar solution compared to free photosensitizer was most significant for the photosensitizer in the PM core. Our results indicate the role of the cargo location in the PM microenvironment and demonstrate that such attempts are fundamental for improving the properties of photosensitizers and their assumed efficiency as nanophotosensitizers in PDT.

Adsorption of C.I. Natural Red 4 onto Spongin Skeleton of Marine Demosponge.

C.I. Natural Red 4 dye, also known as carmine or cochineal, was adsorbed onto the surface of spongin-based fibrous skeleton of Hippospongia communis marine demosponge for the first time. The influence of the initial concentration of dye, the contact time, and the pH of the solution on the adsorption process was investigated. The results presented here confirm the effectiveness of the proposed method for developing a novel dye/biopolymer hybrid material. The kinetics of the adsorption of carmine onto a marine sponge were also determined. The experimental data correspond directly to a pseudo-second-order model for adsorption kinetics (r² = 0.979-0.999). The hybrid product was subjected to various types of analysis (FT-IR, Raman, 13C CP/MAS NMR, XPS) to investigate the nature of the interactions between the spongin (adsorbent) and the dye (the adsorbate). The dominant interactions between the dye and spongin were found to be hydrogen bonds and electrostatic effects. Combining the dye with a spongin support resulted with a novel hybrid material that is potentially attractive for bioactive applications and drug delivery systems.