Poly(trimethylene carbonate)-based porous tubular structures for tissue engineering of small diameter blood vessels

For tissue engineering of small-diameter blood vessels, biodegradable, flexible and elastic porous tubular structures are most suited. In this study, we prepared crosslinked porous tubular structures from poly(trimethylene carbonate) (PTMC), in which smooth muscle cells (SMCs) were seeded and cultured in a pulsatile bioreactor mimicking the physiological conditions. PTMC was synthesized and porous tubular structures were prepared by dipping coating, cross-linking by g-irradiation, and leaching. SMCs were seeded into the porous structures by perfusion and then the constructs were cultured in a pulsatile bioreactor system. The morphologies, mechnical properties were analyzed and SMCs attachment and proliferation were evaluated by histology studies and CyQuant. Flexible tubular structures were obtained by dip coating with 3mm inner diameter and 1mm wall thickness. The porosity of the structures in wet state reached 85 vol% and the pore sizes were 60-150 mm. PTMC tubular structures showed comparable tensile strength and higher elongation compared with natural blood vessels. A pulsatile bioreactor system mimicking the conditions in vivo (dynamic pressure 70 mmHg, 75 beats/min) was successfully built. Experiements showed 7-day dilation was <10% and variation of diameter at each pulse was <1%. SMCs were homogeneously seeded in the porous scaffolds by perfusion. SMCs proliferate well to form confluent cell layer during a time period of up to 14 days, leading to constructs with even better mechanical performance. PTMC Porous tubular structures were prepared with good microstructures, elasticity and biocompatibility. SMCs were seeded and proliferated well in pulsatile bioreactor system and significant improvement of mechnical strength was observed.