El Fons documental de Jordi Verrié i Faget, una aportació a la història de l'educació catalana

El febrer de 2001 moria a Santa Cristina d’Aro Jordi Verrié i Faget, personatge polifacètic que al llarg de la seva vida s’havia dedicat a diferents tasques sempre en defensa i reconeixement de la cultura i la pedagogia catalanes. Investigador incansable, ens deixava un important llegat fruit de la seva passió pels llibres i del seu interès per la nostra història educativa, una part del qual era donat a la Universitat de Girona. Aquest fons documental és el punt de partida d’aquest estudi, que vol aprofundir en la figura de Verrié, contextualitzar el seu fons i valorar què significa per la nostra pedagogia. Aquest és un reconeixement a Jordi Verrié i a la seva tasca, que representa una important aportació a la història de l’educació catalana

The role of counterions in the membrane-disruptive properties of pH-sensitive lysine-based surfactants

Surfactants are among the most versatile and widely used excipients in pharmaceuticals. This versatility, together with their pH-responsive membrane-disruptive activity and low toxicity, could also enable their potential application in drug delivery systems. Five anionic lysine-based surfactants which differ in the nature of their counterion were studied. Their capacity to disrupt the cell membrane was examined under a range of pH values, concentrations and incubation times, using a standard hemolysis assay as a model for endosomal membranes. The surfactants showed pH-sensitive hemolytic activity and improved kinetics at the endosomal pH range. Low concentrations resulted in negligible hemolysis at physiological pH and high membrane lytic activity at pH 5.4, which is in the range characteristic of late endosomes. With increasing concentration, the surfactants showed an enhanced capacity to lyse cell membranes, and also caused significant membrane disruption at physiological pH. This observation indicates that, at high concentrations, surfactant behavior is independent of pH. The mechanism of surfactant-mediated membrane destabilization was addressed, and scanning electron microscopy studies were also performed to evaluate the effects of the compounds on erythrocyte morphology as a function of pH. The in vitro cytotoxicity of the surfactants was assessed by MTT and NRU assays with the 3T3 cell line. The influence of different types of counterion on hemolytic activity and the potential applications of these surfactants in drug delivery are discussed. The possibility of using pH-sensitive surfactants for endosome disruption could hold great promise for intracellular drug delivery systems in future therapeutic applications.