Microneedle applications for DNA vaccine delivery to the skin

Microneedles were initially developed as pretreatment tools for the delivery of therapeutic drugs to intradermal locales in the human skin. Over time, variations in microneedle forms and functions burgeoned through the works of many researchers worldwide. The four major types of microneedles in use today are solid, dissolving, coating, and hollow microneedles. The emergence of different types of microneedles also paved the way for a flourishing diversification of microneedle applications, one of the most remarkable of which deals with the transcutaneous delivery of prophylactic vaccines. Here, we describe fabrication methods of microneedles and DNA vaccine loading methods on the microneedle surface. Furthermore, in the latter part of this chapter, in vivo test protocols for assessing the efficacy of gene delivery using microneedles are described.