Correction to: Microfluidics-Enabled Multimaterial Maskless Stereolithographic Bioprinting (Advanced Materials, (2018), 30, 27, 10.1002/adma.201800242)

Adv. Mater. 2018, 30, 1800242 DOI: 10.1002/adma.201800242 Concerns were raised by a third party regarding duplicated image sections in Figure 4a iv and Figure S5b (Supporting Information), as well as duplicated image panels between -VEGF 15% Day 10 and Day 30 conditions in Figure 5C. The authors acknowledged these issues, attributing them to inappropriate image processing and errors during image compilation. They clarified that these alterations do not impact the scientific findings outlined in the paper. The authors have repeated the underlying experiments for Figure 4a ii–iv to confirm the reproducibility of the results and were also able to provide experimental replicates of the original data for Figure 4a iv. For Figure 5C, the -VEGF 15% Day 10 panel has been replaced with the correct image obtained from the original raw data. Since the original source images for Figure S5 (Supporting Information) were no longer available, the authors have repeated these experiments as well to ensure data integrity. The authors take full responsibility for these errors and sincerely regret any confusion they may have caused. In addition, the authors have made a minor adjustment to the figure panels of Figure 5b to enhance the clarity of presentation. The corrected Figures 4 and 5 and Figure S5 (Supporting Information) are below: Figure 4. a) A tumor angiogenesis model: (i) schematic showing the tumor angiogenesis model; (ii) schematic of the mask for printing; (iii) bioprinted microvasculature in PEGDA; (iv) bioprinted MCF7 cell (blue)-laden microvascular bed of GelMA further seeded with HUVECs (green) in the channels. b) A skeletal muscle model: (i) schematic showing the skeletal muscle tissue; (ii) schematic of the mask for printing; (iii) bioprinted structure of GelMA containing patterned C2C12 cells (red) and fibroblasts (blue) after 48 h of culture; (iv) Presto blue measurements of cell proliferation in the bioprinted structures. c) A tendon-to-bone insertion model: (i) schematic of the tendon-to-bone insertion site; (ii) schematic of the mask for printing; (iii) bright-field optical image showing a bioprinted dye-laden GelMA structure; (iv) bioprinted structure of GelMA containing patterned osteoblasts (blue), MSCs (red), and fibroblasts (green); the inset shows a magnified image of the region hosting fibroblasts, where the cells were stained for f-actin (green) and nuclei (blue). Figure 5. a) A concentration-gradient model generated by multimaterial DMD bioprinting: (i) schematic of the construct showing the PEGDA (35% v/v) frame and three GelMA strips of 5%, 10%, and 15% w/v concentrations with a uniform thickness of 1 mm; (ii) a bioprinted construct where the GelMA strips contained green fluorescent beads to mimic VEGF; (iii) the rat subcutaneous model used to assess the bioprinted constructs. b) Photographs showing the retrieved implants at day 10 and day 30, along with confocal images of the retrieved constructs at day 30 stained for nuclei (blue) and for CD31 (red), where the bright-field views were pseudocolored in green. c) Immunostaining of the retrieved implants for CD31 (red), for different GelMA concentrations (5%, 10%, and 15%), in the absence and presence of VEGF; the nuclei were counterstained with 4′,6-diamidino-2-phenylindole (DAPI) (blue). d) H and E staining of the retrieved implants for different GelMA concentrations, in the absence and presence of VEGF. Figure S5. Effects of washing on the cell viability of bioprinted NIH/3T3-laden GelMA-7% patterns. a) Single-component parallel lines without washing. b) Two-component crossing networks with washing.