Decontamination and disinfection of wastewater by photocatalysis under UV/visible light using nano-catalysts based on Ca-doped ZnO.

Nano-catalysts based on ZnO-Ca x% (with x = 0, 0.1, 0.3, 0.5, 0.7, and 1.0 mol % Ca2+) were synthesized with a bio-friendly adaptation of the sol-gel method using gelatin as template. These materials were characterized by Fourier Transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Micro-Raman, transmission electron microscopy (TEM), scanning electron microscopy (SEM), N2 physisorption, photoacoustic absorption spectroscopy (PAS), and photoluminescence spectroscopy (PL). The Raman results indicated that the signal, attributed to an E1(LO) mode at 580 cm-1, was characteristic of oxygen vacancies that decreased with the increased Ca2+ content in doped oxides. This agreed with the PL results, which showed that the green emission centered at 510 nm and attributable to structural defects in ZnO decreased for Ca-doped ZnO. Our oxides are constituted by nanoparticles with rod-like and spherical morphologies. All the nano-catalysts exhibited the band gap characteristics of semiconductor materials around 3.0 eV. ZnO-Ca 1.0% exhibited the best photocatalytic performance for degradation of Methyl Orange (MO) model dye, degrading about 82% after 240 min of UV-Vis irradiation at pH 7.0. The reaction mechanism was influenced by hydroxyl (OH) and superoxide (O2-) radicals and mainly by active holes (h+). This doped oxide also demonstrated efficiency in wastewater disinfection against heterotrophic bacteria and total coliforms, exhibiting a potential use as an antimicrobial agent for the treatment of hospital wastewater. Furthermore, our nanoparticles did not show significant cytotoxic effects on L929 fibroblast cells.

Cellophane and filter paper as cellulosic support for silver nanoparticles and its thermal decomposition catalysis.

Silver nanoparticles (AgNPs) have attracted great attention due to its optical, electrical and thermal properties. Cellulosic supports for these nanoparticles are of particular interest because of its availability, flexibility and biocompatibility. In this work, AgNPs were synthesized using two cellulosic materials, cellophane (CP) and filter paper (FP), as matrix support. Cellulosic materials were immersed in an aqueous solution of silver nitrate containing polyvinylpyrrolidone (PVP) and then reduced with hydroxylamine. The obtained nanocomposites (CP-AgNPs and FP-AgNPs) were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (DRX) and scanning electron microscopy (SEM). AgNPs of near 15nm anchored onto cellulosic surfaces were detected. The thermal properties of these materials were investigated through thermogravimetry (TG). Their kinetic of thermal decomposition was studied by the Vyasovkin method of dynamic isoconvertion, which indicated a catalytic effect of AgNPs in the cellulose thermal decomposition reaction.

Targeting cancer with nano-bullets: curcumin, EGCG, resveratrol and quercetin on flying carpets.

It is becoming progressively more understandable that different phytochemicals isolated from edible plants interfere with specific stages of carcinogenesis. Cancer cells have evolved hallmark mechanisms to escape from death. Concordant with this approach, there is a disruption of spatiotemproal behaviour of signaling cascades in cancer cells, which can escape from apoptosis because of downregulation of tumor suppressor genes and over- expression of oncogenes. Genomic instability, intra-tumor heterogeneity, cellular plasticity and metastasizing potential of cancer cells all are related to molecular alterations. Data obtained through in vitro studies has convincingly revealed that curcumin, EGCG, resveratrol and quercetin are promising anticancer agents. Their efficacy has been tested in tumor xenografted mice and considerable experimental findings have stimulated researchers to further improve the bioavailability of these nutraceuticals. We partition this review into different sections with emphasis on how bioavailability of curcumin, EGCG, resveratrol and quercetin has improved using different nanotechnology approaches.

Optimization of maghemite-loaded PLGA nanospheres for biomedical applications.

Magnetic nanoparticles have been proposed as interesting tools for biomedical purposes. One of their promising utilization is the MRI in which magnetic substances like maghemite are used in a nanometric size and encapsulated within locally biodegradable nanoparticles. In this work, maghemite has been obtained by a modified sol-gel method and encapsulated in polymer-based nanospheres. The nanospheres have been prepared by single emulsion evaporation method. The different parameters influencing the size, polydispersity index and zeta potential surface of nanospheres were investigated. The size of nanospheres was found to increase as the concentration of PLGA increases, but lower sizes were obtained for 3 min of sonication time and surfactant concentration of 1%. Zeta potential response of magnetic nanospheres towards pH variation was similar to that of maghemite-free nanospheres confirming the encapsulation of maghemite within PLGA nanospheres. The maghemite entrapment efficiency and maghemite content for nanospheres are 12% and 0.59% w/w respectively.

Levan in the developing of new colon-specific polymer material: evaluation of the permeability, moisture and thermal analyses in free films of Eudragit® FS 30 D / Levana no desenvolvimento de novo material polimérico cólon-específico: avaliação da permeabilidade, intumescimento e análises térmicas de filmes isolados de Eudragit® FS 30 D

Levan was used as agent in the synthesis of new colon-specific polymeric matrix together with Eudragit® FS 30 D. Eudragit® FS 30 D films incorporated with levan were made by casting process and characterized to: water vapour transmission, sweeling index, differential scanning calorimetry and thermogravimetric. The levan increased the films permeability (p < 0.001) however did not influenced in the sweeling index of the formulations (p > 0.05). The thermal analyses of the films indicated a glass transition temperature approximate at 47°C and thermal decomposition at 400°C. The results indicated that there is potential for using such site-specificity blend as pharmaceutical coating material.

Levana foi utilizada na síntese de novo material polimérico cólon-específico conjuntamente com o Eudragit® FS 30 D. Filmes de Eudragit® FS 30 D aditivados de levana foram feitos pelo método de "casting process" e caracterizados quanto à transmissão de vapor de água, índice de intumescimento, calorimetria diferencial de varredura e termogravimetria. A levana aumentou a permeabilidade dos filmes (p < 0,001), entretanto não influenciou no índice de intumescimento das formulações (p > 0,05). As análises térmicas dos filmes indicaram uma temperatura de transição vítrea aproximada de 47°C e temperatura de decomposição de 400°C. Os resultados indicaram que há potencial de uso desta nova blenda sítio-específica como material de revestimento farmacêutico.