1:Universidad de Granada; 2:National Institutes of Health; 3:Universidad de Jaén; 4:Biomedical Research Institute of Málaga (IBIMA) Málaga; 5:R&D Bioibérica S.A.U; 6:Instituto de Investigación Biosanitaria ibs.GRANADA; 7:BioFab i3D - Biofabrication and 3D (bio)printing laboratory

In the last few years the 3D bioprinting has shown promising results in the biofabrication of artificial tissues for tissue engineering (TE). Cartilage, as an avascular and stratified tissue, presents a limited capacity of repair; therefore, a severe damage will often require surgical intervention. Many biomaterials, such as PLA, or PCL are being used to create scaffolds for cartilage TE, but, natural‐based materials do not show enough integrity and synthetic‐based materials do not have similar mechanical properties to cartilage such as friction and elasticity which limits their effectiveness and integration in the injury. Here, we evaluated the novel 1,4-butanediol thermoplastic polyurethane elastomer (b-TPUe) filament as a 3D bioprinting material for cartilage TE. The mechanical behaviour of b-TPUe in terms of friction and elasticity were examined and compared with human articular cartilage, PCL, and PLA. Moreover, infrapatellar fat pad-derived human mesenchymal stem cells (MSCs) were bioprinted together with scaffolds and in vitro and in vivo studied were performed. b-TPUe demonstrated a much closer compression and shear behaviour to native cartilage than PCL and PLA, as well as closer tribological properties to cartilage. Moreover, b-TPUe bioprinted scaffolds were able to maintain proper proliferative potential, cell viability, and supported MSCs chondrogenesis. Finally, in vivo studies revealed no toxic effects 21 days after scaffolds implantation, ECM deposition and integration within the surrounding tissue. Our findings indicate that b-TPUe can be exploited for the automated biofabrication of artificial tissues with tailorable mechanical properties including the great potential for cartilage TE applications.