NIR-II probe modified by poly(L-lysine) with efficient ovalbumin delivery for dendritic cell tracking

Dendritic cell (DC) vaccine is an effective strategy for cancer immunotherapy by carrying antigen into DCs and migrating these DCs to drain lymph nodes after inoculation. In this article, second near-infrared window (NIR-II) fluorescent nanoparticles have been used to uptake antigen and activate DCs. Ovalbumin (OVA), an antigen for immunization, can be loaded on the surface of these NIR-II fluorescent nanoparticles via electrostatic interaction by virtue of their functionalized poly(L-lysine) (PLL), which exhibits biocompatibility and strong selective interaction with OVA. In addition, these antigen-loaded complexes can efficiently be engulfed by immature DCs to induce DC maturation and cytokine secretion. After subcutaneous injection, highly sensitive NIR-II fluorescence signal from nanoparticles indicates that nanoparticle-labeled DCs can successfully migrate into lymph nodes in vivo, showing great promise in immunotherapy against cancer.