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Inefficient autologous tissue recovery in diverse skin injuries increases the susceptibility of patients to infections caused by multiresistant microorganisms, resulting in a high mortality rate. Nonviral transfection is an attractive alternative for these patients, where genetically modified cells incorporated into skin substitutes could release additional antimicrobial agents into the native skin. In this work, we have modulated the conditions of using a nonviral system for transfection of primary human keratinocytes and fibroblasts, consisting of a polymer/plasmid DNA (pDNA) complex called polyplex and its effects on the expression of LL-37 antimicrobial peptide. Linear and branched polyethylenimine (PEI) polymers in different weight concentrations were varied for evaluating the formation and colloidal characteristics of the polyplexes. The PEI/pDNA polyplexes with 19 nitrogen/phosphate ratio are nanometric particles (400 and 250 nm with linear and branched PEI, respectively) exhibiting positive surface (+30 ± 2 mV). Both kinds of polyplexes allowed the expression of a reporter gene and increased the human cathelicidin antimicrobial peptide gene expression in transfected keratinocytes and fibroblasts; however, greater cytotoxicity was observed when polyplexes formed with branched PEI were used. Moreover, cell culture supernatants from transfected cells with linear PEI/pDNA polyplexes showed enhanced antimicrobial activity (decrease of bacterial growth in 95.8%) against a

Los organil-amino-alcoxi-silanos son moléculas interesantes para la síntesis de materiales híbridos. Su uso se ha visto limitado debido a la escasa oferta comercial y a su baja estabilidad. En este trabajo se prepararon tres fenil-amino-dietoxi-silanos mediante condensación de fenil-cloro-dietoxi-silano y aminas (ruta 1) y fenil-trietoxi-silano y amiduros de magnesio (ruta 2). La caracterización y los estudios de estabilidad de los compuestos fueron llevados a cabo por 1H-RMN y CG-MS. Ambas rutas presentaron rendimientos mayores a 91%. Fue posible establecer que la sal acida, obtenida en la ruta 1, cataliza la descomposición total de los productos en un tiempo inferior a dos semanas. El medio de reacción de la ruta 2 mostró ser mucho menos agresivo, y después de dos semanas, aún permanece más del 60% de la concentración inicial. Los organil-amino-alcoxi-silanos son moléculas interesantes para la síntesis de materiales híbridos. Su uso se ha visto limitado debido a la escasa oferta comercial y a su baja estabilidad. En este trabajo se prepararon tres fenil-amino-dietoxi-silanos mediante condensación de fenil-cloro-dietoxi-silano y aminas (ruta 1) y fenil-trietoxi-silano y amiduros de magnesio (ruta 2). La caracterización y los estudios de estabilidad de los compuestos fueron llevados a cabo por 1H-RMN y CG-MS. Ambas rutas presentaron rendimientos mayores a 91%. Fue posible establecer que la sal acida, obtenida en la ruta 1, cataliza la descomposición total de los productos en un tiempo inferior a dos semanas. El medio de reacción de la ruta 2 mostró ser mucho menos agresivo, y después de dos semanas, aún permanece más del 60% de la concentración inicial.

Polyaniline-silica composites made with mesoporous silica have been reported to improve the mechanical properties of the free polymer. However, there are not many studies about the effect of the chemical and physical properties of the inorganic material used as hosts over the final properties of polyaniline and the composites. Here, polyaniline-silica composites, exhibiting electrical conductivity, were synthesized using different types of SBA-16 mesoporous silica as hosts. The effects of the characteristics of the hosts in the polymerization kinetic, molecular weight and electrical conductivity of the final polymer were studied. The composites showed higher electrical conductivity in comparison with polyaniline synthesized under similar conditions of this work but in the absence of silica. The use of silica allowed to obtain composites with defined morphology, which did not occur in the absence of these hosts. From the results of this work, it can be concluded that SBA-16 mesoporous silica hosts have a bifunctional role in the formation of polyaniline-silica composites: the hosts behaved like nucleation sites, which favors polymerization of high molecular weight polyaniline and they catalyzed the polymerization reaction, especially when aluminum is present in the structure of the host.