The electrospinning technique allows the production of micro- and nanofibers, which can be used to obtain membranes with high surface area and high porosity. These properties are of importance with regard to the use of nanomaterials in the design of optical detection devices. In this Article, electrospun blends comprising poly­(ethylene oxide) [PEO] and sodium alginate [SA], with and without the adsorption of a fluorescent dye (4-[4-(dimethylamino)­styryl]-1-methypyridinium iodide, [DSMI]), were prepared and characterized. PEO/SA/DSMI nanofibers presented higher fluorescence emission intensity and higher absolute quantum yield compared to DSMI in solution. However, DSMI was leached into the solution during the nanofiber cross-linking process. Thus, in order to avoid this leaching, a xerogel [XSB30] was modified with 4-[4-(dimethylamino)­styryl]­pyridine [DMASP] to generate covalently anchored dye units [XSB30-DMASP]. The resulting novel material was then electrospun with PEO/SA. Cross-linking of the electrospun hybrid PEO/SA/XSB30-DMASP nanofibers produced a material exhibiting an increase in both fluorescence emission and absolute quantum yield. Cellulose acetate [CA] was used for comparison because of its solubility in acetone, a less polar solvent that leads to a better distribution of the xerogel. These electrospun systems associated with fluorescent dyes have the potential to be applied in the design of logical gates and chemical sensors.

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Dyes supported on polymer materials have shown relevance in obtaining optical devices for anionic analyte detection. Thus, in this study, Merrifield resin was functionalized with protonated or silylated perichromic probes, derived from Brooker's merocyanine to be used in chemosensor and chemodosimeter approaches for the detection of anionic species. The phenolic and silylated functionalized resins were characterized by infrared spectrophotometry, thermogravimetric analysis, scanning electron microscopy, and optical and confocal microscopy techniques. These materials were studied in trichloromethane as chromogenic and fluorogenic systems for H 2 PO 4 − , CN − , CH 3 COO − , and F − detection. Furthermore, the functionalized polymers were analyzed by laser scanning confocal microscopy and showed multifluorescence in all cases, due to the fact that the dye is distributed in different microenvironments in the Merrifield resin. These devices have the potential to be studied through multivariate image analysis to obtain faster and simpler results in the detection of anionic analytes.

Poly(lactic acid) (PLA) and poly(ε-caprolactone) (PCL) are two immiscible polymers which are biodegradable and bioabsorbable, being therefore widely applied for medical materials. The formation of homogeneous fibers of PCL by electrospinning represents a difficult task due to the low viscosity of the solutions of this polymer in comparison to the PLA solutions. In addition, the development of simple techniques for the characterization of these systems represents a field of interest. In this paper, nanofibers of PLA/PCL (1:1 w/w) in a CHCl 3 :MeOH (3:1 w/w) solvent system with and without 4-[4-(dimethylamino)styryl]-1-methylpyridinium iodide (DSMI), a perichromic dye, were electrospun. The electrospun nanofibers obtained present a homogeneous diameter distribution, with average of 874 ± 205 nm in optimization condition for PLA/PCL and 627 ± 199 nm for PLA/PCL/DSMI. The analysis of the differences in the fluorescence emission of DSMI distributed in each polymer of the nanofibers allowed the direct investigation of the polymeric domains. It is proposed that these emission differences result from the preferential stabilization of resonant forms of the dye with each polymeric chain. For the PLA−DSMI system, green emission was observed, while for PCL−DSMI, red emission occurred. The fluorescence results corroborated thermal analyses, where the absence of solvents was possible to confirm. The nanofibers were compared with the dye anchored in an xerogel, which did not exhibit different emission regions due to its homogeneous distribution in the matrix.

This work reports the direct synthesis of organochalcogen-modified silver nanoparticles (A1-7), their cytotoxic potentials against glioma cells (C6) and their interaction with DNA. The influence of the presence of electron-withdrawing...

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