Fig. 2.

The role of biophysical properties (such as size, charge, and PEGylation) of biomaterials on the fate of interstitially administrated vaccines targeting LNs. Large vaccines (over 200 nm) exhibit reduced uptake in the lymphatic vessels. However, small vaccines (less than 2 nm) can easily enter blood vessels and result in systemic dissemination. High density PEGylation or anionic surfaces can enhance vaccine accumulation in LNs, but can also hinder their uptake by DCs. Cationic vaccines can exhibit stronger uptake by DCs, but suffer from off-target effects and toxicity.