3D bioprinted hydrogel model incorporating beta-tricalcium phosphatefor calcified cartilage tissue engineering

摘要

One promising strategy to reconstruct osteochondral defects relies on 3D bioprinted three-zonalstructures comprised of hyaline cartilage, calcified cartilage, and subchondral bone. So far, severalstudies have pursued the regeneration of either hyaline cartilage or bone in vitrowhile—despite its keyrole in the osteochondral region—only few of them have targeted the calcified layer. In this work, wepresent a 3D biomimetic hydrogel scaffold containing beta-tricalcium phosphate (TCP)for engineeringcalcified cartilage through a co-axial needle system implemented in extrusion-based bioprintingprocess. After a thorough bioink optimization, we showed that 0.5% w/v TCP is the optimalconcentration forming stable scaffolds with high shape fidelity and endowed with biological propertiesrelevant for the development of calcified cartilage. In particular, we investigate the effect induced byceramic nano-particles over the differentiation capacity of bioprinted bone marrow-derived humanmesenchymal stem cells in hydrogel scaffolds cultured up to 21 d in chondrogenic media. To confirmthe potential of the presented approach to generate a functional in vitro model of calcified cartilagetissue, we evaluated quantitatively gene expression of relevant chondrogenic (COL1, COL2,COL10A1, ACAN) and osteogenic (ALPL, BGLAP) gene markers by means of RT-qPCR andqualitatively by means of fluorescence immunocytochemistry.