Multifunctional particle-constituted microneedle arrays as cutaneous or mucosal vaccine adjuvant-delivery systems.

To overcome drawbacks of current injection vaccines, such as causing needle phobia, needing health professionals for inoculation, and generating dangerous sharps wastes, researchers have designed novel vaccines that are combined with various microneedle arrays (MAs), in particular, with the multifunctional particle-constructed MAs (MPMAs). MPMAs prove able to enhance vaccine stability through incorporating vaccine ingredients in the carrier, and can be painlessly inoculated by minimally trained workers or by self-administration, leaving behind no metal needle pollution while eliciting robust systemic and mucosal immunity to antigens, thanks to delivering vaccines to cutaneous or mucosal compartments enriched in professional antigen-presenting cells (APCs). Especially, MPMAs can be easily integrated with functional molecules fulfilling targeting vaccine delivery or controlling immune response toward a Th1 or Th2 pathway to generate desired immunity against pathogens. Herein, we introduce the latest research and development of various MPMAs which are a novel but promising vaccine adjuvant delivery system (VADS).