Immunostimulatory AIE Dots for Live-Cell Imaging and Drug Delivery

The mechanical properties of nanoscale drug carriers play critical roles in regulating nano-bio interactions. For example, the superior deformability of the softer nanoparticles enables them to pass through the biofilters efficiently, facilitating their long blood circulation and better tumor penetration. However, as a novel nanocarrier system, the elimination efficiency of soft nanoparticles from cells is poorly investigated. Here, we report a facile strategy to prepare soft luminescent nanoparticles through self-assembly of amphiphilic aggregation-induced emission (AIE) fluorophores. The prepared soft AIE dots exhibit strong light emission (quantum yield, ∼27.1%) and can reveal the encapsulation and excretion process of NPs in real time. The cell results showed that soft NPs can greatly increase the transfer speed of nanomaterials into cells and accelerate their elimination from cells through the sacrifice of soft AIE dots. We also show that soft AIE dots loaded with cytosine-phosphate-guanine (CpG) oligodeoxynucleotides can induce strong immunostimulatory effects, producing a high level of various proinflammatory cytokines including tumor necrosis factor (TNF)-R, interleukin (IL)-6, and IL-12. This work demonstrates a new design strategy for synthesizing a soft nanocarrier system that can deliver drugs into cells efficiently and then be eliminated from cells quickly.