Near-Infrared Polymer Dots with Aggregation-Induced Emission for Tumor Imaging

Semiconducting polymer dots (Pdots) have been applied in various biological fields owing to their tunable fluorescence, high brightness, and facile functionalization. However, most Pdots emit in the visible region, wherein fluorescence imaging would suffer from significant photon scattering and autofluorescence in biological tissues. Furthermore, Pdots typically exhibit a reduced fluorescence compared to the corresponding original polymers in organic solvents as a result of aggregation-caused quenching effect. These drawbacks make it difficult to develop Pdots that exhibit bright emission in the near-infrared (NIR) wavelength range. Herein, based on an aggregation-induced emission (AIE) polymer, we report Pdots exhibiting NIR emission along with high fluorescence quantum yield. After fabricating the AIE polymer into Pdots, the fluorescence intensity was enhanced by 2.5-times, yielding NIR emission with a quantum yield of ∼23%. The Pdots also possess outstanding optical properties and biocompatibility, making them a promising imaging agent for in vivo tumor targeting. When the Pdots were used for imaging, the tumor area displayed an intense fluorescence signal and clearly discernible margins, revealing the remarkable potential of the AIE Pdots in bioimaging.