RESUMEN
In this work, pH-sensitive hydrogel nanoparticles based on N-isopropyl acrylamide (NIPAM) and methacrylic acid (MAA) at various molar ratios, were synthesized and characterized in terms of physicochemical and biological properties. FTIR and 1HNMR spectra confirmed the successful synthesis of the copolymer that formed nanoparticles. AFM images and FE-SEM micrographs showed that nanoparticles were spherical, but their round-shape was slightly compromised with MAA content; besides, the size of particles tends to decrease as MAA content increased. The hydrogels nanoparticles also exhibited an interesting pH-sensitivity, displaying changes in its particle size when changes in pH media occurred. Biological characterization results indicate that all the synthesized particles are non-cytotoxic to endothelial cells and hemocompatible, although an increase of MAA content leads to a slight increase in the hemolysis percentage. Therefore, the pH-sensitivity hydrogels may serve as a versatile platform as self-regulated drug delivery systems in response to environmental pH changes.
Asunto(s)
Acrilamidas/síntesis química , Hidrogeles/síntesis química , Ácidos Polimetacrílicos/síntesis química , Acrilamidas/química , Acrilamidas/farmacología , Animales , Células Sanguíneas/efectos de los fármacos , Células Sanguíneas/fisiología , Bovinos , Células Cultivadas , Liofilización , Hemólisis/efectos de los fármacos , Humanos , Hidrogeles/química , Hidrogeles/farmacología , Concentración de Iones de Hidrógeno , Ensayo de Materiales , Metacrilatos/síntesis química , Metacrilatos/química , Nanopartículas/química , Tamaño de la Partícula , Ácidos Polimetacrílicos/química , Ácidos Polimetacrílicos/farmacología , Pruebas de ToxicidadRESUMEN
New aromatic methacrylates were prepared by substitution of a methylene group from diethylaminoethyl methacrylate (DEAEM) by an aromatic ring at two different positions. Diethylamino benzyl methacrylate (DEABM) and N-methacryloyloxyethyl)-N-ethyl-m-toluidine (MEET) were polymerized and incorporated as co-monomers in bone cement formulations. Cements were evaluated in terms of curing and mechanical properties in addition to changes in their glass transition temperature by DSC and surface properties by contact angle measurements. The immediate effect of the presence of an aromatic ring within the amino methacrylate was that it modified the bone cements' physical appearance, as colored products were obtained. It was also observed that peak temperature increased and setting time decreased by the use of DEABM and MEET instead of DEAEM. Simultaneously, both tensile and compressive strength of bone cements were improved; this effect was related to a higher glass transition temperature. In addition, surface properties of cements were modified by the incorporation of the aromatic ring, being more hydrophilic at low molar fractions and more hydrophobic at high molar fractions. Based on these studies, it is concluded that the position of the aromatic ring within the amino methacrylate modified not only the cement's appearance, but also the setting and mechanical properties.
Asunto(s)
Materiales Biocompatibles/química , Cementos para Huesos/química , Metacrilatos/química , Ácidos Polimetacrílicos/química , Ensayo de Materiales , Propiedades de Superficie , Temperatura , Resistencia a la Tracción , Toluidinas/químicaRESUMEN
In this study, starch metabolites and enzymes were determined during starch-based plastic polymer biodegradation by the white rot fungus Phanerochaete chrysosporium, grown in sugarcane bagasse pith in tubular reactors. Various metabolites, amylase, ligninase and cellulase production were measured during P. chrysosporium growth on sugarcane bagasse pith with added glucose and starch polymer. On-line respirometric analyses followed during 32 days confirmed the P. chrysosporium capability of growing on sugarcane bagasse pith with starch polymer degradation. Enzyme activity during secondary metabolism increased, and a 70% and 74% starch degradation was reached with and without glucose addition, generating low molecular weight metabolites (e.g.) dextrin, maltotriose, maltose and glucose that were detected by high performance liquid chromatography.