Fig. 2.

Possible outcomes of a microneedle-coating process. After a certain coating methodology has been employed to coat microneedles, different outcomes are possible with respect to placement of the coatings on the microneedle patch. (i) Coatings are randomly produced and do not uniformly cover the surfaces, (ii) coatings uniformly cover the microneedle shaft but also cover a small region of the substrate near the base of the microneedles, (iii) coatings uniformly cover the entire surface of the patch including the microneedle shafts and the base substrate, (iv) coatings cover just the shaft of the microneedles and do not contaminate the base substrate.