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a b s t r a c tMethylene blue is an electroactive molecule that has been employed for the detection of the DNA hybridization event in electrochemical sensors. However, its use as a covalent label is very scarce and in most of the cases, non-covalent interactions (hydrophobic, electrostatic) are employed. Although it has advantages as simplicity and fewer number of procedure steps, the covalent attachment is less exploited in the development of these sensors. In this article, the electrochemical behavior of methylene blue attached to different DNA-strands is studied. Several lengths (15-and 30-mer) and different degree of DNA modification (MB-DNA, MB-DNA-MB and MB-DNA-SH) have been studied. The highest signals were obtained for longer strands with two MB molecules. In all the cases the signal is enhanced by CNTnanostructuration of the electrode. Adsorption on these modified screen-printed electrodes allowed the amplification by employing an accumulation time. In this way, a sensitivity of −0.2864 A M −1 and a limit of detection of 800 nM for a 120 s accumulation time were obtained.

Poly(methylmethacrylate), PMMA, films filled with titanium oxide, TiO2, nanoparticles were prepared by solution blow spinning, SBS. The influence of the presence of nanoparticles in the physicochemical properties of the material was studied. The PMMA/TiO2 nanocomposites with different amounts of TiO2 (up to 10% by weight) were prepared in the form of films by SBS using a commercial airbrush. Morphology, structure and thermal properties were studied by scanning electron microscopy (SEM), Fourier transformed infrared spectroscopy (FTIR), thermogravimetry (TGA), and differential scanning calorimetry (DSC). It was demonstrated that SBS allowed obtaining PMMA/TiO2 nanocomposites with a relatively high amount of nanoparticles uniformly dispersed within the polymeric matrix. All results point out that the macromolecular flow, forced by the SBS process, so as the specific interactions and the TiO2 surface induce a preferential conformation of the ester group respect to the PMMA backbone, at least when the number of aggregates low enough.

method was found highly dependent of the reagent and activation temperature, highlighting the possibility to design micro-mesoporous carbon xerogels at low temperatures with a subtle control of the activation conditions.