Figure 2: Biomaterial-based vaccine strategies.

Therapeutic vaccine modalities can be divided into two main categories dependent on primary material modality. Particulate-based vaccines (left) include nanoparticle, including liposomes, and extracellular vesicles such as exosomes. Polymer-based vaccines (right) can either be biodegradable or non-degradable and can be composed of polymers, hydrogels or silica rods.