High-modulus, melt spun polycaprolactone fibres for biomedical grafts

The mechanical requirements for a graft or regenerative tissue scaffold can vary depending on the expected load and healing time for such a device. For synthetic tendon repair the graft should have mechanical properties that facilitate its surgical introduction and fixation and be capable of withstanding high tensile loading with limited extension during the recovery phase. Tendons have a tensile strength of 50 to 150 MPa and an elastic modulus of 550 MPa and upwards [1-3]. Finding a suitable synthetic material is often a compromise between mechanical performance and biocompatibility. Polycaprolactone (PCL) is known to have excellent properties as a biomaterial due to the favorable cytotoxic and cell growth response observed in vitro and in vivo. In addition, the biological breakdown time for PCL is acceptable for applications where the graft is expected to bear load for an extended period of healing [3]. However, the measured tensile properties of as-spun PCL is insufficient for high tenacity and high modulus applications [4, 5]. The post-spinning drawing of polycaprolactone is one option for increasing the mechanical properties of PCL.