Microneedle (MN) arrays are minimally-invasive devices used to penetrate the skin’s outermost layer, the stratum corneum, the principal barrier to topically-applied drugs. They are widely used in a range of applications including cosmetics and pharmaceuticals. Their use involves a simple, cheap, safe, and effective technique requiring minimal training. Microneedles were originally used as a collagen induction therapy for facial scars and skin rejuvenation, and still are, but are also now widely used in the form of patches as a transdermal delivery system for therapeutic drugs and vaccines.
