Modelling the 3D bioprinting process of β-sheet self-assembling peptide hydrogel scaffolds

Extrusion-based three-dimensional (3D) bioprinting is nowadays the most efficient additive manufacturing technology to fabricate well-defined and clinical-scale relevant 3D scaffolds, exploiting soft biomaterials. However, trial and error approaches are usually employed to achieve the desired structures, thus leading to a waste of time and material. In this work, we show the potential of finite element (FE) simulation in predicting the printability of a biomaterial, in terms of extrudability and scaffold mechanical stability over time. To this end, we firstly rheologically characterized a newly developed self-assembling peptide hydrogel (SAPH). Subsequently, we modelled both the extrusion process of the SAPHs as well as the stability over time of a 3D bioprinted wood-pile scaffold. FE modelling revealed that the simulated SAPHs and printing set-ups led to a successful extrusion, within a range of shear stresses that are not detrimental for cells. Finally, we successfully 3D bioprinted a human ear-shaped scaffolds with in vivo dimensions and several protrusion planes by bioplotting the SAPH into a poly(vinyl alcohol)-poly(vinyl pyrrolidone) copolymer, which was identified as a suitable bioprinting strategy by mechanical FE simulation.