Fabrication and characterization of the bioinspired multifunctional MNs. (a) Schematic illustrations of the fabrication process. (b–d) Optical images of the MNs: an intact MN patch (b) and corresponding magnified images (c, d). (e–g) SEM images showing the suction-cup-structured concave chambers. The scale bars are 5 mm in (b), 1 mm in (c), 300 μm in (d, e), and 100 μm in (f, g).