The Importance of Particle Shape: Effect of Nonspherical Particles and Their Stabilized Pickering Emulsions on Immunization Efficacy

Adjuvants based on spherical particles and stabilized Pickering emulsions represent a significant area of research in the adjuvant field. However, the immune effects of adjuvants containing nonspherical particles and their stabilized Pickering emulsions remain largely unexplored. Particle shape plays a critical role in influencing particle-cell interactions and antigen storage efficiency. In this study, it is aimed to synthesize nonspherical particles with diverse morphologies and sizes and successfully utilize one type to stabilize Pickering emulsions. In this research, their immunological effects are further evaluated by examining the activation of antigen-presenting cells (APCs) and their impact on both cellular and humoral immunity. In these findings, it is demonstrated that nonspherical particles extend the in vivo residence time of vaccines and enhance APCs activation, thereby improving cellular immunity. Additionally, Pickering emulsions stabilized by nonspherical particles exhibit superior flexibility, higher antigen uptake by APCs, and more robust APCs activation compared to those stabilized by spherical particles. These advantages ultimately result in enhanced humoral and cellular immune responses.