review of recent literature on microneedle vaccine delivery technologies

Anto Vrdoljak Development Laboratory, Genera, Rakov Potok, Croatia Abstract: Microneedles (MNs) have been developed as medical devices for enhanced and painless transdermal drug and vaccine delivery. MN-based vaccine application, unlike conventional intramuscular or subcutaneous application using hypodermic needles, delivers vaccine directly into skin, which is known to be an immunologically much more relevant vaccination site than underlying tissue. Vaccination using MN devices targets the skin's rich immune system, leading to better utilization of the antigen and resulting in superior immune response, often achieved using a lower vaccine dose than required by conventional delivery routes. However, despite the number of advantages and nearly four decades of research, the number of licensed MN-based vaccines remains limited to date. Nevertheless, it is to be expected that on the back of a number of recently developed scalable and robust MN-fabrication methods, more intensive translation into clinical practice will follow. Here, we review the current status and trends in research of MN-related vaccine delivery platforms, focusing on the most promising approaches and clinically relevant applications. Keywords: microneedles, vaccine delivery, skin vaccination