Figure 3.

The effects of rapid printing on part quality and cellular function in large-sized models. A–E) Demonstration of FLOAT printing process of a centimeter-sized human hand model. Sequential images of the hand model that was continuously formed in 10% PEGDA 400 Da preploymer pool at 5 min, 10 min, and 15 min and completed at 20 min. It would take 6.5 h to print the same model using traditional layer-by-layer printing method. D) The length of the completed hand model is 5.6 cm. E) Fingers were easily bent under compression, showing the compliance of the hydrogel hand model. F) Hand model printed in 2 h using the traditional layer-by-layer SLA process. Severe layer detachment and finger distortion occurred due to dehydration. G) 3D reconstructed image of FLOAT-printed hand model from MRI scanning. The channels were visualized with the aid of a contrast agent. Metabolic activity and cytotoxicity measured by H) XTT assay and I) LDH assay shortly after the printing of centimeter-sized, cell-laden samples. Cells in FLOAT-printed samples experienced much less printing-induced injury and have much higher metabolic activity than those in layer-by-layer printed samples. The above cell-laden samples were printed using 7% GelMA plus 2% PEGDA 8 kDa. n = 9. All box plots with whiskers represent the data distribution based on five number summary (maximum, third quartile, median, first quartile, minimum). **, p < 0.001; *, p < 0.05; #, p = 0.1 determined by two-tailed t-test.