3D printed scaffolds with core-shell structure for bone tissue engineering

Abstract

Biomaterials with core-shell structure have been used as carriers for drug delivery applications and cell encapsulation, allowing several improvements in the field of tissue engineering. Although the usefulness of biomaterials with this morphology has been already proved in several studies, the development of core-shell fibrous structures by 3D printing technologies could be the key to the advancement of their applications at a larger scale. The aim of this project is to generate tridimensional scaffolds with core-shell fibrous morphology and drug-delivery capability, using a direct ink writing method, for bone regeneration purposes. Self-supporting alginate-based hydrogel inks and self-setting alpha tricalcium phosphate-based cement inks were optimized, and 3D printed core-shell structure scaffolds were successfully generated by direct ink writing, with either a hydrogel-hydrogel or a cement-hydrogel core-shell composition. Afterwards, cement-hydrogel core-shell 3D printed scaffolds with dual drug-delivery capability were designed. Cobalt ions, which have pro-angiogenic effect, and Cytochrome C, a model protein simulating BMP-2 osteogenic factor, were loaded in the hydrogel shell and the cement core of the printed scaffolds, respectively. The evaluation of their delivery kinetics which showed a burst release of both factors, allowed to prove the dual drug delivery potential of the 3D printed cement-hydrogel core-shell scaffolds generated in this study.