Micro-groove patterned PCL patches with DOPA for rat Achilles tendon regeneration

Abstract

Achilles tendon regeneration using current tissue engineering techniques requires morphometrically mimetic tendon biomaterials to attain the required microstructural tendon tissue and to achieve the necessary mechanical properties. In this study, we used nano- (400 nm) and micro-groove (5000 nm) patterned polycaprolactone patches (PCL-400, PCL-5000), which offer adequate elastic modulus and biocompatibility. The PCL patches were fabricated via capillary force lithography and were surface modified with 3,4-dihydroxy-l-phenylalanine (DOPA) for increased hydrophilicity. We hypothesized that the resulting biologically surface-modified elastic groove patterned patches would enhance the cell behaviors in vitro and the rat Achilles tendon regeneration in vivo. The micro-groove patterned PCL patches with DOPA coating (DOPA-PCL-5000) exhibited excellent cell elongation, tenogenic differentiation and YAP expression of the mesenchymal stem cells in our in vitro study and these results were further confirmed by application to the rat Achilles tendon rupture model in our in vivo study. DOPA-PCL-5000 induced dramatic regeneration of rat Achilles tendon compared to the other groups, which was further confirmed by the Achilles functional index and histological analysis at 8 weeks. In conclusion, DOPA-PCL-5000 can be used not only for damaged Achilles tendon, but also for various functional tendon regeneration techniques such as rotator cuff, patellar tendon, and flexor tendon.