Electrospun silk fibroin-gelatin composite tubular matrices as scaffolds for small diameter blood vessel regeneration.

In this work an innovative method to obtain natural and biocompatible small diameter tubular structures is proposed. The biocompatibility and good mechanical properties of electrospun silk fibroin tubular matrices (SFts), extensively studied for tissue engineering applications, have been coupled with the excellent cell interaction properties of gelatin. In fact, an innovative non-cytotoxic gelatin gel, crosslinked in mild conditions via a Michael-type addition reaction, has been used to coat SFt matrices and obtain SFt/gel structures (I.D. = 6 mm). SFts/gel exhibited homogeneous gelatin coating on the electrospun fibrous tubular structure. Circumferential tensile tests performed on SFts/gel showed mechanical properties comparable to those of natural blood vessels in terms of UTS, compliance and viscoelastic behavior. Finally, SFt/gel in vitro cytocompatibility was confirmed by the good viability and spread morphology of L929 fibroblasts up to 7 days. These results demonstrated that SFt/gel is a promising off-the-shelf graft for small diameter blood vessel regeneration.