Fig. 3.

(A) Modes of presentation of pattern-recognition receptor (PRR) agonists (depicted as red-filled hexagon) to polymeric nanoparticles: (a) by encapsulation and (b) by surface display, achieved through physical and chemical interactions. (B) Polymeric nanoparticles incorporated with PRR agonists target PRRs that are located at different cellular domains to shape adaptive immune responses. The polymeric nanoparticles can target TLR1, TLR2, TLR4, and TLR6 at cell membrane. Cellular uptake of the nanoparticles leads to signalling endosomal TLRs including TLR3, TLR7, TLR8, and TLR9. Escaping the endosomes is required to target RIG-I, NOD1 and NOD2 at cytosol, as well as STING at endoplasmic reticulum. (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)