• A Microparticulate Vaccine Microneedle patch for pain-free Immunization against Coronavirus Disease

      Vijayanand, Sharon; Patil, Smital R.; Joshi, Devyani; D'Souza, Martin J. (2021)
      Microneedle (MN) patches for vaccine delivery is an effective immunization strategy suitable for mass immunization. Here, we test the level of immunity provided by a microparticulate (MP) heat-inactivated coronavirus vaccine when administered via the skin as pain-free dissolving MN patches. The vaccine formulation utilizes an MP matrix that provides protection of the antigen and improved antigen uptake by antigen-presenting cells (APCs). The microparticles (MPs) were formulated using a double emulsion method, lyophilized, characterized, and assessed for their in vitro immunogenicity. The in vivo efficacy of the MP vaccine was tested in mice. The immunization was done in 3 doses. ELISA was done to assess the IgG level in mice sera. The animals were sacrificed at week 10 and their organs were harvested for further analysis and expression of immune markers. The results show that the MPs were less than 1 microns in size and the MP vaccine induced a strong innate immune response in vitro. Serum analysis showed higher IgG levels of the vaccine groups. The vaccine groups showed a higher expression of antigen-presenting molecules. Based on the results, we summarize that the MP vaccine can produce an effective immune response when administered as an MN patch via the skin. Moreover, MN patches allow self-administration, which greatly increases patient compliance in addition to decreasing the need for trained pharmacists for immunization.