Design of novel three-phase PCL/TZ-HA biomaterials for use in bone regeneration applications

The design of bioactive scaffold materials able to guide cellular processes involved in new-tissue genesis is key determinant in bone tissue engineering. The aim of this study was the design and characterization of novel multi-phase biomaterials to be processed for the fabrication of 3D porous scaffolds able to provide a temporary biocompatible substrate for mesenchymal stem cells (MSCs) adhesion, proliferation and osteogenic differentiation. The biomaterials were prepared by blending poly(epsilon-caprolactone) (PCL) with thermoplastic zein (TZ), a thermoplastic material obtained by de novo thermoplasticization of zein. Furthermore, to bioactivate the scaffolds, microparticles of osteoconductive hydroxyapatite (HA) were dispersed within the organic phases. Results demonstrated that materials and formulations strongly affected the micro-structural properties and hydrophilicity of the scaffolds and, therefore, had a pivotal role in guiding cell/scaffold interaction. In particular, if compared to neat PCL, PCL-HA composite and PCL/TZ blend, the three-phase PCL/TZ-HA showed improved MSCs adhesion, proliferation and osteogenic differentiation capability, thus demonstrating potential for bone regeneration.