Fig. 2

Morphology and degradation of GelMA/PEGDA MNs. a Preparation process GelMA MNs. b Physical picture of MNs patch. c, d SEM images of MNs. Scale bar in C: 500 μm, scale bar in D: 100 μm. e–g Degradation experiment of MNs (Day 1, Day 3, Day 5), scale bar: 200 μm. h–j Partial enlarged view of white box of scale bar: 100 μm