Printability during projection-based 3D bioprinting

Since projection-based 3D bioprinting (PBP) could provide high resolution, it is well suited for printing delicate structures for tissue regeneration. However, the low crosslinking density and low photo-crosslinking rate of photocurable bioink make it difficult to print fine structures. Currently, an in-depth understanding of the is lacking. Here, a research framework is established for the analysis of printability during PBP. The gelatin methacryloyl (GelMA)-based bioink is used as an example, and the printability is systematically investigated. We analyze the photo-crosslinking reactions during the PBP process and summarize the specific requirements of bioinks for PBP. Two standard quantized models are established to evaluate 2D and 3D printing errors. Finally, the better strategies for bioprinting five typical structures, including solid organs, vascular structures, nerve conduits, thin-wall scaffolds, and micro needles, are presented.