Research Progress of Microneedles in Vaccine Delivery

Large-scale infectious diseases have become a significant threat to human health and safety. The successful invention of vaccines is the most powerful means for preventing infectious diseases and has greatly improved global human health. Even during the pandemic of COVID-19, which has affected the world, vaccines have played an irreplaceable role. Microneedles (MNs) punctured the stratum corneum and formed microchannels in the skin allowing the vaccine to be efficiently recognized by the abundant antigen-presenting cells (APCs) in the skin to form specific immunity. Compared with traditional vaccination methods, MN transdermal immunization has the advantages of painlessness, easy storage, and efficient immune response. In this review, we summarize the types of vaccines, types of MNs, research progress and clinical research status of MN-based vaccines. We also cover various technologies for vaccine encapsulation, stable delivery of MN vaccines, and a wide range of potential clinical applications. We also outline the future development prospects of the MN system onboard to achieve better clinical benefits.