Manufacture of elastic biodegradable PLCL scaffolds for mechano-active vascular tissue engineering

A soft and very elastic poly(lactide-co-epsilon-caprolactone) (PLCL)(50:50, Mn 185 x 10(3)) was synthesized. Tubular scaffolds were prepared by an extrusion-particulate leaching method for mechano-active vascular tissue engineering. The copolymer was very flexible but completely rubber-like elastic. Even the high porous PLCL scaffolds (90% salt wt) exhibited 200% elongation, but recovery over 85% in a tensile test. Moreover, the PLCL scaffolds maintained their high elasticity also in culture media under cyclic mechanical strain conditions. The highly porous scaffold (90% salt wt) withstood for an initial 1 week without any deformation and sustained for 2 weeks in culture media under cyclic stress of 10% amplitude and at 1 Hz frequency which are similar to the natural vascular conditions. Vascular smooth muscle cells (VSMCs) were seeded on to the PLCL scaffolds. The cell adhesion and proliferation on the scaffolds of various pore-size were increased with increasing pore size. For the pore sizes of 50-100 microm, 100-150 microm, 150-200 microm and 200-250 microm, the ratios of cell numbers were about 1:1.2:1.9:2.2, respectively, at both 12 h and 5 days. Similarly, the higher porous scaffolds exhibited more cell adhesion and proliferation compared to lower porous one, where the effect was more pronounced in the longer proliferation period. SMC-seeded scaffolds were implanted subcutaneously in athymic nude mice to confirm the biocompatibility. Such a high elastic property and proper biocompatibility to SMCs of PLCL scaffolds prepared in this study will be very useful to engineer SM-containing tissues such as blood vessels under mechanically dynamic environments (mechano-active tissue engineering).