Fluorescent polymeric microspheres are used in a wide range of biomedical and technological applications, including blood flow determination, screening, flow visualization, flow tracing, medical imaging, fluorescence microscopy and flow cytometry among others. Rhodamine 6G (R6G) is a lipophilic cationic dye, which is among the most stable organic fluorophores, and with a high quantum yield in fluorescence (absorption and emission) in the visible range (500-600 nm). It is mainly applied in laser technology, and also in fluorescent bioimage. In this work we present an efficient synthesis route to obtain Polyvinyl Alcohol/Polyvinyl Acetate (PVA/PVAc) spherical microparticles containing Rhodamine 6G in a concentration sufficient to exploit their fluorescent properties. The synthesis method comprises the suspension polymerization of Vinyl acetate (VAc) monomer in the presence of Rhodamine, followed by saponification. Microspheres loaded with 1.9% w / w of Rhodamine 6G were obtained. They presented good sphericity and a size distribution in the range of 20 to 1550 microns. The fluorescence intensity of the microspheres was measured by UV-Vis and fluorescence spectroscopy, and detected using an image-based experimental setup, respectively. The results obtained with these methodologies showed that our microspheres exhibit fluorescence and that they are quite detectable in water flows. However, the response of UV-Visible fluorescence and absorbance was affected by the presence of the PVA / PVAc polymer matrix.

ABSTRACT In the present work, the effect of commonly consumed beverages such as coffee, mate, tea and mineral water on the surface chemical composition of a commercial glass ionomer is studied. Ionomer samples were prepared according to the manufacturer; they were placed within infusions and stationed on culture stove at 36 ° C in the range of 21 hours to 33 days. The evolution of the chemical composition at different storage times was studied by Proton Induced X-Ray Emission (PIXE) technique. In all media except mineral water, to long times, the loss of Al, Si and Na was determined, suggesting the partial dissolution of Na aluminumsilicate. The concentration profile of Al and Si were different in every way, but the ratio Al: Si remained close to unity in all cases. The F was released associated with Na in mineral water, while in the rest of the beverages its concentration profile infers the formation of fluorinated compounds of Ca and La. Simultaneously, the adsorption of Mn, Mg and Fe to the glass ionomer surface was observed, not previously reported in the literature.

RESUMEN En el presente trabajo se estudia el efecto de bebidas de consumo habitual como café, mate, té y agua mineral en la composición química de la superfície de un ionómero de vidrio comercial. Las muestras de ionómero se prepararon según las indicaciones del fabricante; se colocaron en las infusiones y se estacionaron en estufa de cultivo a 36 °C en el rango de 21 horas hasta 33 días. La evolución de la composición química a diferentes tiempos de almacenamiento se estudió mediante la técnica de Emisión de Rayos X inducida por Protones (PIXE). En todos los medios, excepto agua mineral, a tiempos largos se determinó la pérdida de Al, Si y Na, esto sugiere la disolución parcial de un aluminosilicato de Na. El perfil de concentración de Al y Si fue diferente en todos los medios, pero la relación Al:Si se mantuvo cercana a la unidad en todos los casos. El F se liberó asociado con Na en agua mineral, mientras que en el resto de bebidas su perfil de concentración infiere la formación de compuestros fluorados de Ca y La. Simultáneamente se observó la incorporación de Mn, Mg y Fe en la superficie del ionómero vítreo, no reportada anteriormente en la literatura.