Abstract
The key role and impact of nanotechnology in vaccine development became particularly prominent following the outbreak of the coronavirus disease 2019 (COVID-19) pandemic in 2019. Especially in the process of designing and optimising COVID-19 vaccines, the application of nanomaterials significantly accelerated vaccine development and efficient delivery. In this review, we categorised and evaluated conventional vaccines, including attenuated live vaccines, inactivated vaccines, and subunit vaccines, highlighting their advantages and limitations. We summarised the development history, mechanisms, and latest technologies of vaccine adjuvants, emphasising their critical role in immune responses. Furthermore, we focused on the application of nanotechnology in the vaccine field, detailing the characteristics of nanoparticle vaccines, including virus-like particles, lipid-based carriers, inorganic nanoparticles, and polymer-based carriers. We emphasised their potential advantages in enhancing vaccine stability and immunogenicity, as well as their ability to deliver vaccines and present antigens through various routes. Despite facing challenges such as low drug loading efficiency, issues with long-term storage, high costs, and difficulties in large-scale production, nano-vaccines hold promise for the future. This review underscores the pivotal role and prospects of nanotechnology in vaccine development, offering new pathways and strategies to address current and future disease challenges.