Fig. 2

Microscopic morphologies and drug-releasing performance of the MNs patches. a Fluorescence stereomicroscope images of the surface morphology and overall view of drug-free (above) and drug-loaded (below) MNs. b SEM images of MNs before and after being pressed on mice skin for 1, 5, 15 and 30 min, respectively. c Fluorescence morphology image of Rhodamine B loaded MNs. d Fluorescence top-view (above) and section-view (below) images of mice skin treated by Rhodamine B loaded MNs for 1 min