An AIE-based self-assembled fluorescent probe for COX-2 imaging

Cyclooxygenase-2 (COX-2), an isozyme of the cyclooxygenase enzyme family, is not only high-expressed in various types of tumors, but also over-expressed in all stages of cancers. Herein, we report the design and preparation of an aggregation-induced emission (AIE) based fluorescent probe TPI-IMC for the imaging of COX-2 by the conjugation of 4-(1,4,5-triphenyl-1H-imidazol-2-yl) pyridine (TPI) and COX-2 inhibitor indomethacin (IMC). TPI-IMC exhibits weak fluorescence in normal cells (LO2 cells and RAW264.7 cells), while it shines stronger fluorescence in the cells overexpressing COX-2 such as cancer cells (HeLa cells) and inflammatory cells (LPS induced RAW264.7 cells). It is also found that the significantly reduced fluorescence intensity is observed and detected in HeLa cells co-treated with the COX-2 inhibitor celecoxib. Therefore, TPI-IMC has the potential to be used as a guiding-agent in surgery for tumour and inflammation.