Reversible photoswitching conjugated polymer nanoparticles for cell and ex vivo tumor imaging

摘要

Fluorescent photoswitchable conjugated polymer nanoparticles (PCPNPs) bearing poly(9,9-dihexylfluorene-a/t-2,l,3-benzoxadiazole) (PFBD) as the fluorescent host polymer and the photochromic diarylethene as toggle are synthesized via a modified nano-precipitation method using 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[amino(polyethylene glycol)-2000] (DSPE-PEG-NH2) as the encapsulation matrix. The PCPNPs are spherical in shape with diameters around 34 nm. The fluorescence switching processes upon UV-and white light illumination are successfully demonstrated with high contrast up to 90-fold, recovery efficiency of 95%, and excellent repeatability in solution. The cationic PCPNPs can be easily internalized into cancer cells, and accumulate in tumor tissues, where the fluorescence photoswitching processes can be used to self-validate the imaging results.