Figure 21.

(A) In vivo handheld printing device aspect and composition of GelMA-LAP BMI, loaded with VEGF. The aim of this BI and the handheld device was to treat skeletal muscle injuries through in situ 3D printing. (B) Photographs of muscle-induced injury. Step 3 shows the handheld printing process, and Step 4 shows the finished restoration surgery. (C) Optical microphotographs of scratch assay with HUVEC cells. “Fresh” results belonged to GelMA-LAP/VEGF BMI crosslinked and subjected to scratch assay at time 0; “Presoaked” scratch assay was performed with crosslinked GelMA-LAP/VEGF BMI pre-soaked in DPBS for 24 h before scratch assay; “Negative” control was composed of growth medium without VEGF; “Positive” control test was performed by means of growth medium supplemented with 30 ng/mL of VEGF. Figures adapted with permission from [63], IOP Publishing, 2021.