Investigation of mechanical properties and degradability of multi-channel chitosan-polycaprolactone/collagen conduits

Multi-channel chitosan-polycaprolactone (CH-PCL)/collagen conduits were fabricated for potential applications in long-gap peripheral nerve repair. CH-PCLs with various PCL percentages changing from around 30 to 45 wt% were used for the fabrication of conduits, and the collagen content in the conduits was controlled at about 8 wt% or less in order to ensure the required mechanical strength and degradation rate of the resulting conduits. The porosity and average channel diameter of the conduits with a dimension of around 5 mm in outer diameter and 30 mm in length were optimized as around 80% and 200 μm, respectively. Swelling index, compressive load, deformation recovery and bending stiffness of the conduits were measured, respectively. In vitro degradation measurements was conducted in phosphate buffer saline, and results revealed that the effect of collagen content on the degradation rate of the conduits was not significant until the degradation time reached around 6 weeks. After being implanted into rabbits for various durations, the degradation of the conduits appeared to be strongly dependent on the collagen content in addition to the dependence on the degradation time. After 10-week in vivo degradation, some conduits that contained 6 wt% or less content of collagen still showed shape integrity and required compressive mechanical properties, suggesting that the degradation rate of the conduits can be effectively regulated by the collagen content while the required properties for the conduits would be well maintained.