Electrospun meshes of poly (n-butyl cyanoacrylate) and their potential applications for drug delivery and tissue engineering.

The aim of the present work was to develop novel meshes of poly (n-butyl cyanoacrylate) (PBCA) nanofibers for potential applications in drug delivery and tissue engineering taking into account the successful application of PBCA in other medical uses. Electrospinning was applied to solutions of PBCA, 103 and 106 Da. 5-fluorouracil was chosen as model drug for the delivery study because of its effectiveness against cancer, while human gingival fibroblasts (HFIB-G) to confirm the biocompatibility of drug-free PBCA meshes and their potential for tissue engineering. PBCA was able to be electrospun in a wide range of molecular weights, producing fibers free of defects with diameters between 380 nm and 6 µm. Meshes of PBCA (105-106 Da) showed high flexibility with Younǵs modulus and maximal tension values in the range of 0.3-1.6 MPa and 0.03-0.13 MPa respectively. Results from the drug delivery study suggested that 5-fluorouracil was homogeneously loaded into PBCA meshes. Its release was extremely slow, initially 20% in 7 days and the rest gradually (until 96 days) in physiological medium at 37 °C. HFIB-G were well attached and proliferated over PBCA nanofibers during 23 days. Results suggested that PBCA meshes serve as excellent frameworks for cell adhesion/proliferation, and for drug delivery extended periods.

Determinación de la profundidad de curado y propiedades mecánicas de composites dentales fotopolimerizables experimentales / Depth of cure and mechanical properties of experimental light-cured composite resins

En el presente trabajo se estudian la resistencia a la compresión, módulo encompresión, resistencia a la compresión diametral, dureza, desgaste y profundidad decurado de seis formulaciones de composites dentales fotopolimerizables. Los compositesfueron preparados usando como matrices combinaciones de Bis-GMA/DMATEEG, Bis-GMA/MPS, Bis-GMA/DMATEEG/MPS. Como relleno se utilizó cuarzo del yacimiento „ElCacahual‰ y la combinación de cuarzo/aerosil 200. La resina VenusTM Heraus Kulzer fueutilizada como material de referencia. La profundidad de curado se determinó según normaISO 4049. Para las determinaciones de la resistencia a la compresión, módulo en compresión,resistencia a la compresión diametral se utilizó la máquina universal de ensayosBIONIX. El desgaste se realizó en una máquina pin-on-disc, utilizando papeles abrasivos deSiC 1200 y 600 grip. Se obtuvo que las formulaciones con mejores propiedades son aquellasque tienen como sistema monomérico el Bis-GMA/DMATEEG/MPS

The aim of this study was to determine the compressive strength, compressivemodulus, diametrical tensile strength, Vickers hardness, wear resistance and depth ofcure of six light-cured dental composites. The matrix were Bis-GMA/TEEGDMA, Bis-GMA/MPS, Bis- GMA/ TEEGDMA/ MPS. Quartz of «El Cacahual» and combinations quartzaerosil200 were used as inorganic fillers. It was used as reference material the commercialresin VenusTM Heraus Kulzer. Depth of cure was determined according to ISO 4049.For the determinations of the compressive strength, module, diametrical tensile strengththe universal machine of rehearsals BIONIX was used. The waste was carried out in amachine pin-on-disc, using abrasive papers of SiC 1200 and 600 grip. As a result, the formulationswith better properties are those that have as monomeric system the Bis-GMA/TEEGDMA/MPS