A tumor-targeting and polarity-specific near-infrared fluorescent probe for accurate cancer diagnosis in vivo

Abstract

Although the cure rate of cancer is very low, the survival rate of patients can be improved if it is diagnosed early and treated in time. Polarity, as a significant parameter of tumor microenvironment, is bound up with the development of cancer. Unfortunately, there is currently no report about tumor-targeted and polarity-specific NIR fluorescent probe for accurate cancer diagnosis. Here, a polarity-specific near-infrared (NIR) fluorescent probe named CX-P based on coumarin-xanthene dye is reported. The probe has the advantages of long emission wavelength (>650 nm) and outstanding tumor targeting ability. CX-P is highly sensitive to polarity, and has a linear range from Δƒ = 0.284 (30% water) to Δƒ = 0.321 (100% water). Moreover, the probe can actively target cancer cells and display strong red fluorescence, while the fluorescence in normal cells is negligible. CX-P is also used to real-time monitor the polarity changes after the treatment of cancer cells with LPS, sucrose and taxol. Based on its NIR characteristics, CX-P is applied to real-time imaging of tumor-bearing mice and the significant tumor targeting ability is further confirmed. As far as we know, this is the first tumor-targeting and polarity-specific NIR fluorescent probe, which will offer a powerful means for accurate cancer diagnosis in the future.