Hypoxia-Responsive Luminescent CEST MRI Agent for and Tumor Detection and Imaging.

Hypoxia is a feature of most solid tumors and a key determinant of cancer growth and propagation. Sensing hypoxia effectively could lead to more favorable clinical outcomes. Here, we report a molecular antenna-based bimodal probe designed to exploit the complementary advantages of magnetic resonance (MR)- and optical-based imaging. Specifically, we describe the synthesis and evaluation of a dual-action probe () that permits hypoxia-activated chemical exchange saturation transfer (CEST) MR and optical imaging. In CT26 cells, this probe not only provides an enhanced CEST MRI signal but also turns "on" the optical signal under hypoxic conditions. Time-dependent CEST imaging in a hypoxic CT26 tumor xenograft mouse model revealed probe-dependent tumor detection by CEST MRI contrast in the tumor area. We thus suggest that dual-action hypoxia probes, like that reported here, could have a role to play in solid tumor diagnosis and monitoring.