Strategy for enhancing mechanical properties and bone regeneration of 3D polycaprolactone kagome scaffold: Nano hydroxyapatite composite and its exposure

Although attempts to improve tissue-engineering scaffolds have been made using composite materials (synthetic polymers, bioceramics, etc.), research on bone tissue engineering has been limited to improving mechanical properties because of the intrinsic drawbacks of the grid-type structures conventionally used as scaffolds. To overcome this limitation, this study proposes a polycaprolactone/nano-hydroxyapatite scaffold with a kagome structure formed via material-extrusion process. The kagome structure is reported to be a mechanically superior open-pore structure. The mechanical properties and in vitro cell activities of 3D scaffolds have been studied with respect to the nano-hydroxyapatite (nHA) content in the scaffold. The compressive modulus of the PCL/nHA scaffold with kagome structure was found to be significantly improved. In addition, nHA particles on the surface of the scaffold were exposed through alkaline erosion, improving bone-regenerating ability. The alkaline erosion did not affect the structural characteristics of the scaffold, including pore size, porosity, hydroxyapatite content, and compressive modulus. Additionally, we observed that the exposure of PCL/nHA particles promoted bone-regeneration activity through enhanced osteoconduction of the scaffold.