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

Abstract

Cyclooxygenase-2 (COX-2), an isozyme of the cyclooxygenase enzyme family, is not only highly expressed in various types of tumors, but also over-expressed in all stages of cancer. 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). The probe was applied for the detection and imaging of COX-2, and a linear range from 0 to 0.4 μg mL⁻¹ and a detection limit of 0.08 μg mL⁻¹in vitro were achieved. TPI-IMC exhibits weak fluorescence in normal cells (LO2 cells and RAW264.7 cells), while it exhibits stronger fluorescence in the cells over-expressing COX-2 such as cancer cells (HeLa cells) and inflammatory cells (LPS induced RAW264.7 cells). It is also found that 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 tumours and inflammation.