Digital light processing of customized elastic scaffolds by efficient thiol-yne crosslinking

Digital light processing (DLP) based 3D printing technology has the advantages of fast printing rate and high spatial resolution in the manufacture of tissue engineering scaffolds. However, the limited availability of printable materials for DLP technology, especially the lack of biodegradable elastomeric materials hinders the development of customized soft tissue scaffolds. Herein, liquid poly(4-methyl-epsilon-caprolactone) dialkynylate (PMCLDY) was prepared as a DLP printable ink based on efficient thiol-yne photocrosslinking. With the aid of photorheology and in situ FT-IR and tensile tests, an ink formulation for DLP printing was optimized as the P50 ink (PMCLDY to diluent PEGDY mass ratio of 1), which possessed fast cure rates (<15 s), low viscosity (<2 Pas), moderate mechanical properties (failure strain > 40 %) and maximum toughness (0.153 MJm(-3)). A commercial DLP printer equipped with the P50 ink realized 3D scaffolds models with microstructure and macroscopic shape precisely. It was demonstrated that the 3D printed scaffold with biodegradability could withstand dynamic compression cycles. Furthermore, the cytocompatibility experiments showed that the scaffold could effectively support the growth and proliferation of rat bone marrow stromal cells (BMSCs). These results demonstrate that the P50 ink is a promising material for manufacturing elastic scaffolds by DLP printing for tissue engineering applications.