Figure 4.

Microneedle patch (MNP) for influenza vaccination. (a) The MNP contains an array of 100 microneedles measuring 650 μm tall that is mounted on an adhesive backing. (b) The MNP is manually administered to the wrist, enabling self-administration by study subjects. (c) Microneedles encapsulate influenza vaccine (represented here by blue dye) within a water-soluble matrix. (d) After application to the skin, the microneedles dissolve, thereby depositing vaccine in the skin and leaving behind a patch backing that can be discarded as non-sharps waste. (Reprinted with permission from Ref. [81]).