Utilizing direct-initiation of thiols for photoinitiator-free stereolithographic 3D printing of mechanically stable scaffolds

Abstract

Abstract The automated production of artificial biological structures for biomedical applications continues to gather interest. Different fields of science are combined to find solutions for the arising multidimensional problems. Additive manufacturing in combination with material science provides one solution for the biological issues around 3D cell culture and construction of living tissues. Here, we present the photoinitiator-free stereolithographic fabrication of thiol-ene polymers with microarchitectures in the range of tens of microns for scaffolds up to the millimeter scale. Scaffolds composed of cubic unit cells were designed using computer-aided design (CAD) and subsequently 3D printed with a custom-made laser stereolithography setup. The process parameters were determined step by step with increasing complexity and number of parameters. Gained insights were applied to the fabrication of 3D printed test specimens. The quality of the 3D printed parts was evaluated by measuring the porosity and optical microscopy images. Furthermore, the mechanical properties of the scaffold structures were characterized using compression testing and compared with the bulk material revealing a lower capacity to bear load but higher flexibility. In this study, we demonstrate the advantages of combining the high-precision, freeform fabrication of stereolithography with a biocompatible material for the fabrication of complex microarchitectures for biomedical applications