CONICET | Buscador de Institutos y Recursos Humanos

In this work, electrospun matrices of PLLA/SPU 50/50 blend (as the inner layer of vascular grafts) were surface modified through the immobilization of heparin and lysozyme, as anticoagulant and antibacterial, respectively. The modification through ester and urethane functional groups was explored. In the ester route, an alkaline treatment was employed to increase the density of PLLA reactive carboxylic groups. Then, diaminoPEG (DAPEG) was employed as spacer to avoid a reduction in heparin activity due to limited mobility. In the urethane route, a NaClO treatment was employed to activate SPU urethane functional groups. Further modification with allyl glycidyl ether generated epoxy-capped oligomers. This step was followed by DAPEG modification. From then on, both routes followed with heparin modification. Moreover, a matrix prepared by each route was exposed to a lysozyme solution to form a heparin-lysozyme complex, due to lysozyme has a relatively low stability in its free state. MSC proliferation on modified scaffolds resulted in the order of the control, being higher for the lysozyme modified scaffolds. Cell proliferation reached its maximum at day 7. After this, the values decreased for all scaffolds. It was previously reported that a high proliferation inhibits further cell growth. Moreover, live-dead staining showed cells were able to growth onto the scaffolds, displaying better cytocompatibility the matrices obtained through urethane route. Lysozyme activity was evaluated through m. lysodeikticus suspensions. The immobilized lysozyme remained active for both modification routes, being more active the matrix obtained through urethane route. Thus, from the obtained results, it can be concluded that the urethane route seems to be the most promising for covalent modification of PLLA/SPU 50/50 blends.