Fig. 3: Mechanical performance of the IMAP.

a Mechanical curves of the IMAP during the P&R test. b OCT images of skin penetration by the MA during the press stage, c solid microneedles retract from the skin to the medical sponge during the release stage, and d poked skin after the ‘P&R’ test. e The mechanical stability of the MA assessed by the insertion ratio of the intact poked microholes to the microneedle number, and pictures of skin samples treated with the IMAP at (e1) the 1st, (e2) the 10th and (e3) the 20th cycle of the ‘P&R’ action. f SEM image of the microhole in the rabbit skin poked by the IMAP after the 20th cycle, and g–h SEM images of the MA of the IMAP after the 20th cycle.