Figure 12.

Hollow microneedle patch for chronic infected wounds [173], with permission from Wiley. (a) The design inspiration for porous and hollow microneedles comes from the structure and biological behavior of corals. (b) The inside room of the porous microneedle shell is filled with drug carrying hydrogel. The bottom opening window of microneedle is placed on the back of the patch. (c) The microneedle patch could penetrate the scab shell on the surface of the wound and collect exudate from the tissue.