Nanoparticle Vaccines Adopting Virus-like Features for Enhanced Immune Potentiation

Chattopadhyay, Saborni; Chen, Jui-Yi; Chen, Hui-Wen; Hu, Che-Ming Jack

Gold's unique malleability makes AuNPs an attractive platform for vaccinology studies [103] . AuNPs can be fabricated into myriad of shapes (i.e. sphere, rod, cube, etc.) [104] with tunable yet sharply distributed size range between 2-250 nm [105] . This morphological tunability adds an additional dimension of virus mimicry with the introduction of non-spherical particles. Gold nanorods, for instance, have been used as a vaccine vector for the delivery respiratory syncytial virus (RSV) F protein [106] . These non-spherical particles bear resemblance to rod-like viruses that can also be frequently observed among different virus genera [107] . The size modularity of AuNPs also allows for examining the impact of particle size on vaccine delivery, which will be discussed in details in later sections of this review. Also worth noting is the more recent discovery that AuNP size and shape can modulate the inflammatory responses at the cellular level [104] . In a study that compares gold nanospheres, gold nanorods, and gold nanocubes, Niikura et al. showed that whereas the nanospheres and the nanocubes induced tumor necrosis factor-α (TNF-α), IL-6, IL-12, and granulocyte macrophage colony-stimulating factor (GM-CSF), the nanorods induced interleukin-1β and interleukin-18 via an inflammasome-dependent mechanism [104] . This shape-dependent immunological property may be due to the differing surface energies associated with different nanoscale features, which may promote varying levels of stress upon cellular uptake [108] .