Vat photopolymerization bioprinting with a dynamic support bath

Support bath-assisted additive manufacturing has been extensively employed in constructing 3D complex soft biomaterials by extrusion- or inkjet-based printing. However, the conventional support bath (i.e., slurry of gelatin microparticles used in freeform reversible embedding of suspended hydrogels and nanoclay) can only provide static in-situ support to the deposited constructs, which is not feasible for vat photopolymerization printing since the printed constructs are mobile during the printing process. A dynamic support bath assisted vat photopolymerization printing method using yield stress fluid (YSF) is proposed in this study, which enables the dynamic accompanying supporting for the printing structures. As the moving platform rises continually, the YSF bioink was elevated with the cured construct near the curing region and remaining in a solid-like state to provide support against gravity and surface tension. While the YSF bioink was in a liquid-like state, due to the atmospheric pressure difference during the rising of moving platform, the YSF bioink can flow to fill up the vacuum and ensure continuous forming. Thus, this printing method achieved the vat photopolymerization printing of extremely soft cell-laden bioinks (Young's modulus of 4.3 KPa) into 3D complex constructs with excellent biological functionality.

Automated summary

In this study, a dynamic support bath assisted vat photopolymerization printing method using yield stress fluid (YSF) was proposed. The YSF bioink can provide dynamic support to the printing structures by solidifying near the curing region and filling up the vacuum, enabling continuous forming during the rising of the moving platform. This method successfully achieved vat photopolymerization printing of extremely soft cell-laden bioinks into 3D complex constructs with excellent biological functionality.