Reinforced alginate/gelatin sponges functionalized by avidin/biotin-binding strategy: a novel cardiac patch

Adequate mechanical properties to withstand the surgical procedure and decoration with bioactive molecules promoting tissue regeneration are crucial aspects in the development of successful matrices for cardiac tissue engineering. The aim of this work was the development of a novel cardiac patch based on a blend of alginate and gelatin, designed to combine the improvement of suture resistance with an effective growth factor immobilization. We defined the procedures to incorporate a poly(dioxanone) membrane within the alginate/gelatin sponges and to functionalize the biomaterial with insulin-like growth factor-1, using the avidin–biotin-binding strategy. Morphological analysis of the reinforced scaffolds showed a porous structure and a good adhesion of the synthetic microporous membrane to the natural sponge. Infrared chemical imaging analysis demonstrated the efficacy of the chemical treatments performed for scaffold reinforcement and functionalization. A good hydrophilicity and an adequate permeability were shown by swelling and permeability tests. The inclusion of the synthetic membrane improved the viscoelastic properties, as measured by dynamic mechanical analysis, and the suture retention force under both dry and wet conditions. The in vitro and in vivo biological characterization showed that insulin-like growth factor-1 functionalization successfully enhanced cell adhesion and long-term retention after implantation on the damaged myocardium, together with improved suturability by poly(dioxanone) reinforcement.