Adhesive free-standing multilayer films containing sulfated levan for biomedical applications

This work is the first reporting the use of layer-by-layer to produce adhesive free-standing (FS) films fully
produced using natural-based macromolecules: chitosan (CHI), alginate (ALG) and sulfated levan (L-S).
The deposition conditions of the natural polymers were studied through zeta potential measurements
and quartz crystal microbalance with dissipation monitoring analysis. The properties of the FS films were
evaluated and compared with the control ones composed of only CHI and ALG in order to assess the influence
of levan polysaccharide introduced in the multilayers. Tensile tests, dynamic mechanical analysis
and single lap shear strength tests were performed to evaluate the mechanical properties of the prepared
FS films. The presence of L-S conferred both higher tensile strength and shear strength to the developed
FS membranes. The results showed an adhesion strength 4 times higher than the control (CHI/ALG) FS
films demonstrating the adhesive character of the FS films containing L-S. Morphological and topography
studies were carried out revealing that the crosslinking reaction granted the L-S based FS film with a
higher roughness and surface homogeneity. Preliminary biological assays were performed by cultivating
myoblasts cells on the surface of the produced FS films. Both crosslinked and uncrosslinked FS films containing L-S were cytocompatible and myoconductive.