Reversible redox 19F magnetic resonance imaging nanoprobes for monitoring the redox state in vivo†

Redox processes are indispensable for physiology, and dysregulated redox balance is critical in various metabolic diseases. The development of imaging diagnosis tools for real-time monitoring of the redox state in vivo is of great importance yet highly challenging. Here, we designed trifluoromethyl (–CF₃) grafted selenide polymer nanoprobes for reversible redox sensing in vivo. Based on the reversible shift of the ¹⁹F-nuclear magnetic resonance (NMR) peak between oxidation and reduction states of the nanoprobes exposed to different redox species, the ¹⁹F-magnetic resonance imaging (MRI) signal ratio of S_Ox/(S_Ox + S_Red) was successfully applied to monitor the redox state in a tumor. These nanoprobes demonstrated good biocompatibility and great potential for exploring physiological and pathological redox processes in deep tissues. We envision that this work will enable the rational design of ¹⁹F-MRI nanoprobes with excellent redox response for the real-time monitoring of the redox state at the lesion location.