Tailoring functional nanoparticles for oral vaccine delivery: Recent advances and future perspectives

The oral vaccine has attracted much interest due to easy administration, induction of local and systemic immune responses, and pain relief. Nowadays, functional nanoparticles and nanocomposites consisting of inorganic and organic materials as carriers or adjuvants have shown the enhanced antigen absorption in the gut and improved immune response via oral routes. This review summarizes the advances and challenges of functional nanoparticles and nanocomposites for oral vaccine delivery, including the key barriers of the mucosal delivery, the transport mechanisms of these nanoformulation through the epithelial layer, and the key physicochemical properties of the nanoparticles and nanocomposites for antigen delivery. Various nanoformulations including nanoparticles and nanocomposites were further exemplified. The summary and expert opinions in designing functional nanoformulation for efficient oral vaccine delivery are provided.