Chondro-Inductive b-TPUe-Based Functionalized Scaffolds for Application in Cartilage Tissue Engineering

Osteoarthritis is a disease with a great socioeconomic impact and mainly affects articular cartilage, a tissue with reduced self-healing capacity. In this work, 3D printed 1,4 butanediol thermoplastic polyurethane (b-TPUe) scaffolds are functionalized and infrapatellar mesenchymal stem cells are used as the cellular source. Since b-TPUe is a biomaterial with mechanical properties similar to cartilage, but it does not provide the desired environment for cell adhesion, scaffolds are functionalized with two methods, one based on collagen type I and the other in 1-pyrenebutiric acid (PBA) as principal components. Alamar Blue and confocal assays display that PBA functionalized scaffolds support higher cell adhesion and proliferation for the first 21 days. However, collagen type I functionalization induces higher proliferation rates and similar cell viability than the PBA method. Further, both functionalization methods induce extracellular matrix synthesis, and the presence of chondrogenic markers (Sox9, Col2a, and Acan). Finally, SEM images probe that functionalized 3D printed scaffolds present much better cell/biomaterial interactions than controls and confirm early chondrogenesis. These results indicate that the two methods of functionalization in the highly hydrophobic b-TPUe enhance the cell-biomaterial interactions and the improvement in the chondro-inductive properties, which have great potential for application in cartilage tissue engineering.