Electrospun biphasic tubular scaffold with enhanced mechanical properties for vascular tissue engineering.

Polymer scaffolds produced through an electrospinning process are frequently explored as tissue substitutes for regenerative medicine. Despite offering desirable surface area to volume ratios and tailorable pore sizes, their poor structural mechanical properties limit their applicability in load-bearing regions. In this study, we present a simple strategy to improve the mechanical properties of a vascular graft scaffold. We achieved the formation of biphasic tubular scaffolds by electrospinning polyurethane (PU) onto an airbrushed tube made of polycaprolactone (PCL). After preparation, the scaffold was subsequently thermally-crosslinked (60°C) to strengthen the bonding between the two materials. The tensile strength and tensile elastic (Young's) modulus of the biphasic scaffolds were significantly enhanced from 4.5±1.72 and 45±15MPa (PU-only) up to 67.5±2.4 and 1039±81.8MPa (PCL/PU; p<0.05). Additionally, suture retention force, burst pressure, and compliance were all improved. The cytotoxicity of the fabricated samples was investigated using an MTT assay after 7days of cell culture and found to be negligible (~100% viability). In conclusion, we have demonstrated the preparation and characterization of a stable and mechanically robust vascular graft scaffold using a novel combination of well-established fabrication techniques. This study could also be extended to the fabrication of other biphasic scaffolds to better enhance the mechanical properties of the electrospun fibers mat without deteriorating its architecture structure.