Carbonic Anhydrase Inhibitor-decorated Semiconducting Oligomer Nanoparticles for Active-Targeting NIR-II Fluorescence Tumor Imaging.

Second near-infrared window (NIR-II) fluorescence imaging has shown great potential in the field of bioimaging. To achieve a better imaging effect, variety of NIR-II fluorescence probes have been designed and developed. Among them, semiconducting oligomers (SOs) have shown unique advantages including high photostability and quantum yield, making them promise in NIR-II fluorescence imaging. Herein, we design a semiconducting oligomer nanoparticle (ASONi) for NIR-II fluorescence imaging of tumor. ASONi is composed of an azido-functionalized semiconducting oligomer (ASO) as the NIR-II fluorescence emitter, and a benzene sulfonamide-ended DSPE-PEG (DSPE-PEG-CAi) as the stabilizer. Owing to the benzene sulfonamide groups on the surface, ASONi has the capability of targeting the carbonic anhydrase IX (CA IX) of MDA-MB-231 breast cancer cell. Compared with ASON without benzene sulfonamide groups on the surface, ASONi has a 1.4-fold higher uptake for MDA-MB-231 cells and 1.5-fold higher breast tumor accumulation after i.v. injection. The NIR-II fluorescence signal of ASONi can light the tumor up within 4 h, demonstrating its capability of active tumor targeting and NIR-II fluorescence imaging.