Converging chondrogenic aggregates and melt electrowriting for the fabrication of patient-specific implants

Abstract

Articular cartilage defects are common and they strongly affect the quality of life of the patients and lead to a significan healthcare burden. Current treatments are hampered by the avascularity of the tissue and eventually do not provide an appropriate tissue repair, especially in the long term. Biofabrication techniques have been taking hold in the cartilage regeneration field to develop potential alternatives to current treatments. However, scaffolds lack to resemble the native tissue both biologically and in terms of mechanical properties. The inclusion of cells in scaffolds was shown to allow degradation to occur in tandem with tissue formation and the use of 3D culture systems can potentially lead to a more precise resemblance of the natural cell microenvironment. The aim of this study was to use extrusion-based bioprinting to deposit Articular cartilage chondroprogenitor cells (ACPCs) aggregates included in gelatin methacryloyl (gelMA) inside melt electrowritten “box-like” scaffolds. We aimed to reproduce both the cartilage component and the fibre-reinforcing component of the native tissue by converging the two biofabrication techniques, together with the use for the first time of ACPCs aggregates. In this study, we bioprinted on top of flat and tilted surfaces, showing the possibility to fabricate scaffolds with anatomically relevant angles, thus shapes. The metabolic activity was investigated and no significant difference was found over 7 days, suggesting its mantainance over the evaluated period of time. Upon quantification of the aggregate viability, no significant difference was found over the same period on top of flat and tilted substrates. This study suggests that the combination of extrusion-based bioprinting of aggregates and melt electrowriting is promising to achieve implants tailored according to anatomically relevant shapes.