Soft lithography using acryloxy perfluoropolyether composite stamps

This paper describes composite patterning elements that use a commercially available acryloxy perfluoropolyether (a-PFPE) in various soft lithographic techniques, including microcontact printing, nanotransfer printing, phase-shift optical lithography, proximity field nanopatterning, molecular scale soft nanoimprinting, and solvent assisted micromolding. The a-PFPE material, which is similar to a methacryloxy PFPE (PFPE-DMA) reported recently, offers a combination of high modulus (10.5 MPa), low surface energy (18.5 mNm(-1)), chemical inertness, and resistance to solvent induced swelling that make it useful for producing high fidelity patterns with these soft lithographic methods. The results are comparable to, and in some cases even better than, those obtained with the more widely explored material, high modulus poly(dimethylsiloxane) (h-PDMS).     

Analysis of anatoxin-a in biological samples using liquid chromatography with fluorescence detection after solid phase extraction and solid phase microextraction

Anatoxin-a is a naturally occurring, potent neurotoxin produced by some species of cyanobacteria in freshwaters. This toxin, which is a potential health hazard, especially to animals, has been determined in different biological matrices such as several cyanobacterial cultures and water samples and carps and mussels tissue using a sensitive High Performance Liquid Chromatography with Fluorescence detection method. Sonication was the technique selected for the extraction of intracellular anatoxin-a and solid phase extraction using weak cation exchange was used for the concentration and purification of the samples. 4-Fluoro-7-nitro-2,1,3-benzoxadiazole (NBD-F) was used to convert anatoxin into a highly fluorescent derivative. Recovery experiments were performed for each type of matrix used in this work, and adequate values were obtained (71-87%). Limits of detection for anatoxin-a were estimated to be in the ng/L and ng/g level for water and cyanobacterial samples, respectively. The results obtained were also compared with those obtained after using solid phase microextraction, as an alternative for the extraction and purification of the samples. Advantages and disadvantages regarding to the efficiency for impurities removal, simplicity and rapidity and the potential for concentration enhancement of using both methodologies have been also discussed.     

A New Chalcone Derivative with Promising Antiproliferative and Anti-Invasion Activities in Glioblastoma Cells

Glioblastoma (GBM) is the most common and most deadly primary malignant brain tumor. Current therapies are not effective, the average survival of GBM patients after diagnosis being limited to few months. Therefore, the discovery of new treatments for this highly aggressive brain cancer is urgently needed. Chalcones are synthetic and naturally occurring compounds that have been widely investigated as anticancer agents. In this work, three chalcone derivatives were tested regarding their inhibitory activity and selectivity towards GBM cell lines (human and mouse) and a non-cancerous mouse brain cell line. The chalcone 1 showed the most potent and selective cytotoxic effects in the GBM cell lines, being further investigated regarding its ability to reduce critical hallmark features of GBM and to induce apoptosis and cell cycle arrest. This derivative showed to successfully reduce the invasion and proliferation capacity of tumor cells, both key targets for cancer treatment. Moreover, to overcome potential systemic side effects and its poor water solubility, this compound was encapsulated into liposomes. Therapeutic concentrations were incorporated retaining the potent in vitro growth inhibitory effect of the selected compound. In conclusion, our results demonstrated that this new formulation can be a promising starting point for the discovery of new and more effective drug treatments for GBM.     

Green solvents for enhanced impregnation processes in biomedicine

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Synthesis and structural characterization of novel pyranoluteolinidin dyes

The synthesis and structural characterization by LC–MS and NMR of novel pyranoluteolinidin derivatives are reported. The compounds result from the reactions between luteolinidin and three different carboxylic acids in wine model-like solutions. The three pigments possess different substituents attached to the D ring (methyl, catechol and dimethylaminophenyl groups) and the same catechol group in the B ring, yielding a wide spectrum of colors from yellow to pink-purple.     

Simple Methodology for the Quantitative Analysis of Fatty Acids in Human Red Blood Cells

In the last years, there has been an increasing interest in evaluating possible relations between fatty acid (FA) patterns and the risk for chronic diseases. Due to the long life span (120 days) of red blood cells (RBCs), their FA profile reflects a longer term dietary intake and was recently suggested to be used as an appropriate biomarker to investigate correlations between FA metabolism and diseases. Therefore, the aim of this work was to develop and validate a simple and fast methodology for the quantification of a broad range of FAs in RBCs using gas chromatography with flame ionization detector, as a more common and affordable equipment suitable for biomedical and nutritional studies including a large number of samples. For this purpose, different sample preparation protocols were tested and compared, including a classic two-step method (Folch method) with modifications and different one-step methods, in which lipid extraction and derivatization were performed simultaneously. For the one-step methods, different methylation periods and the inclusion of a saponification reaction were evaluated. Differences in absolute FA concentrations were observed among the tested methods, in particular for some metabolically relevant FAs such as trans elaidic acid and eicosapentaenoic acid. The one-step method with saponification and 60 min of methylation time was selected since it allowed the identification of a higher number of FAs, and was further submitted to in-house validation. The proposed methodology provides a simple, fast and accurate tool to quantitatively analyse FAs in human RBCs, useful for clinical and nutritional studies.

     

Theoretical Design and Experimental Realization of Quasi Single Electron Enhancement in Plasmonic Catalysis

By a combination of theoretical and experimental design, we probed the effect of a quasi‐single electron on the surface plasmon resonance (SPR)‐mediated catalytic activities of Ag nanoparticles. Specifically, we started by theoretically investigating how the E‐field distribution around the surface of a Ag nanosphere was influenced by static electric field induced by one, two, or three extra fixed electrons embedded in graphene oxide (GO) next to the Ag nanosphere. We found that the presence of the extra electron(s) changed the E‐field distributions and led to higher electric field intensities. Then, we experimentally observed that a quasi‐single electron trapped at the interface between GO and Ag NPs in Ag NPs supported on graphene oxide (GO‐Ag NPs) led to higher catalytic activities as compared to Ag and GO‐Ag NPs without electrons trapped at the interface, representing the first observation of catalytic enhancement promoted by a quasi‐single electron.     

Mechanochemical synthesis of some europium diketonates

Results on the influence of mechanoactivation (3–30 min) in a planetary ball mill on the composition, crystal structure, IR spectra and morphology of EuCl₃·6H₂O, dibenzoylmethane (HDBM) and mixtures of EuCl₃·6H₂O — HDBM and EuCl₃·6H₂O — HDBM — 1,10-phenathroline (phen) are presented. Mechanoactivation leads to a decrease of interplanar distances of the EuCl₃·6H₂O and HDBM and partial synthesis of Eu(DBM)₃ and Eu(DBM)₃·phen in the respective mixtures. The fluorescence properties of the products of activation (excitation and emission spectra, lifetime of the excited states) are similar to those of the complexes produced by the conventional “wet” methods, but the strongest excitation of the mechanochemically produced solid state samples is achieved at higher wavelength. Crystals of different forms (prismatic, needle-, long-length-leaf- and rod-like) are formed by mechanoactivation of the mentioned mixtures.     

Disposable solid state probe for optical screening of chlorpromazine

We are presenting a simple, low-cost and rapid solid-state optical probe for screening chlorpromazine (CPZ) in aquacultures. The method exploits the colourimetric reaction between CPZ and Fe(III) ion that occurs at a solid/liquid interface, the solid layer consisting of ferric iron entrapped in a layer of plasticized PVC. If solutions containing CPZ are dropped onto such a layer, a colour change occurs from light yellow to dark pink or even light blue, depending on the concentration of CPZ. Visual inspection enables the concentration of CPZ to be estimated. The resulting colouration was also monitored by digital image collection for a more accurate quantification. The three coordinates of the hue, saturation and lightness system were obtained by standard image processing along with mathematical data treatment. The parameters affecting colour were assessed and optimized. Studies were conducted by visible spectrophotometry and digital image acquisition, respectively. The response of the optimized probe towards the concentration of CPZ was tested for several mathematical transformations of the colour coordinates, and a linear relation was found for the sum of hue and luminosity. The limit of detection is 50???M (corresponding to about 16???g per mL). The probe enables quick screening for CPZ in real water samples with prior sample treatment.