abstractThe synthesis of new environmentally friendly products with antimicrobial activity, applied to the formulation of coatings that prevent biofilm formation is an issue that has become important in recent years. Biofilms produce undesirable changes (biodeterioration) in material properties due to the vital activity of microorganisms. They reduce indoor air quality by contributing to the formation of bioaerosols and therefore affect human health. This paper aims to greensynthesis and characterization of solid silica matrix associated with copper and silver, as counter cations of a heteropolyacid for use as antimicrobial additives in paints. The solids were obtained from the sol-gel method using different acidic medium. The antifungal activity of the synthesized solids was evaluated against two fungal isolates, Alternaria alternata and Chaetomium globosum, obtained from biodeteriorated paints films. Different silicas were prepared using tetraethyl orthosilicate and methyltrimethoxysilane as precursors and acids as catalysts for the hydrolysis reaction of the alkoxide. Once the synthesis phase and the characterization of the samples were finished, the antifungal activity against the microorganisms selected was evaluated and the inhibition percent was determined in each case. Among the solids tested, most showed antifungal activity, because they inhibited the fungal growth at the lower concentrations compared to the sample without the solids, although the presence of copper and silver increases the inhibition in most cases.

ResumenLa síntesis de nuevos productos con actividad antimicrobiana, amigables con el medio ambiente, aplicados a la formulación de recubrimientos que prevengan la formación de biopelículas es un tema que ha cobrado gran relevancia en los últimos años. Las biopelículas producen cambios indeseables (biodeterioro) en las propiedades de los materiales como consecuencia de la actividad vital de los microorganismos. Por otro lado, afectan la salud humana, al constituirse en el interior de las viviendas y disminuir la calidad del aire por contribuir con la formación de bioaerosoles. El presente trabajo tiene como objetivo la síntesis verde y la caracterización de sólidos de matriz silícea asociados con cobre y plata, como contracationes de un heteropoliácido para su uso como aditivos antimicrobianos en pinturas. Los sólidos se obtienen a partir del método sol-gel mediante diferentes medios ácidos. La actividad antifúngica de los sólidos sintetizados se evaluó frente a dos aislamientos fúngicos, Alternaria alternata y Chaetomium globosum, obtenidos a partir de películas de pinturas biodeterioradas. Se prepararon sílices empleando tetraetilortosilicato y metiltrimetoxisilano como precursores y catalizadores ácidos para la reacción de hidrólisis del alcóxido. Una vez finalizada la etapa de síntesis y caracterización de las sílices propuestas, se evaluó su actividad antifúngica frente a los hongos de interés y se determinó el porcentaje de inhibición en cada caso. De los sólidos ensayados, la mayoría mostraron tener actividad antifúngica por inhibir el crecimiento de ambos hongos con las menores concentraciones en relación a su blanco, aunque los que contenían cobre y plata presentaron un mayor grado de inhibición en todos los casos.

The objective of this work was to synthesize nanosilicas with different degree of hydrophobicity by the sol-gel method, using tetraethyl orthosilicate as a precursor. For this purpose, 3-aminopropyl triethoxysilane (APS) and 1,1,1,3,3,3 - hexamethyldisilazane (HMDS), were added during synthesis as modifiers. A commercial biopolymer (Hexamoll Dinch, BASF) intended for packaging of apples, was added to the new nanosilicas. The materials obtained were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, potentiometric titration, porosity, specific surface area and hydrophobicity/hydrophilicity by wetting test. Colorimetry was used to evaluate change in apple pulp color after contact with the different silicas.