RESUMO
The development of small-caliber grafts still represents a challenge in the field of vascular prostheses. Among other factors, the mechanical properties mismatch between natural vessels and artificial devices limits the efficacy of state-of-the-art materials. In this paper, a novel nanocomposite graft with an internal diameter of 6â¯mm is proposed. The device is obtained through spray deposition using a semi-interpenetrating polymeric network combining poly(ether)urethane and polydimethilsyloxane. The inclusion of BaTiO3 nanoparticles endows the scaffold with piezoelectric properties, which may be exploited in the future to trigger beneficial biological effects. Graft characterization demonstrated a good nanoparticle dispersion and an overall porosity that was not influenced by the presence of nanoparticles. Graft mechanical properties resembled (or even ameliorated) the ones of natural vessels: both doped and non-doped samples showed a Young's modulus of â¼700â¯kPa in the radial direction and â¼900â¯kPa in the longitudinal direction, an ultimate tensile strength of â¼1â¯MPa, a strain to failure of â¼700%, a suture retention force of â¼1.7â¯N and a flexural rigidity of â¼2.5â¯×â¯10-5â¯Nâ¯m2. The two grafts differed in terms of burst strength that resulted â¼800â¯kPa for the control non-doped samples and â¼1100â¯kPa for the doped ones. The graft doped with BaTiO3 nanoparticles showed a d33 coefficient of 1.91 pm/V, almost double than the non-doped control. The device resulted highly stable, with a mass loss smaller than 2% over 3 months and an excellent biocompatibility.