Filmes de galactomanana-colágeno: caracterização físico-química e uso na detecção de lectinas

Abstract

This work reports the application of galactomannan:collagen films as piezoelectric biosensor for detection of lectins. The films, casted in acrylic molds, from collagen solutions containing galactomannan in various proportions (1:1, 3:2, 7:3 and 4:1), were crosslinked with glutaraldehyde (0.001 to 1.5 %). The study of interactions of lectins with films was by affinity columns utilizing a film in a spiral in nylon spacer, where the mobile phase is forced to pass between them. The swelling studies of collagen films with galactomannan in that variable proportions, showed that the water swelling can be controlled by the galactomannan concentration and the glutaraldehyde crosslink treatment, which best concentration was 0,1%. However in films with high galactomannan concentration can occur lixiviation of the gum not occluded by the collagen net. Hemagglutination activity were determined to evaluate the binding of lectins on the films and the yield, calculated per membrane surface was expressed by mass of lectin µg /area and was 76.8 µg/cm2 for galactomannan:collagen film (3:2). The piezoelectric strain tensor element d14, the elastic constant s55, and the dielectric permittivity Eli were obtained for the galactomannan:collagen (3:2 and 7:3 w/w) films, doped or not with lectin. Resonance measurement of the piezoelectric strain constant d14 of galactomannan:collagen film gives 0.080 pC/N. It was observed that adsorption onto the film slightly increased the piezoelectricity to 0.088 pC/N and decrease the film resonance frequency of 0f--- 5,7 MHz. These results open the possibility of using this films in electronic devices for galactose binding lectin detection from vegetal extracts.