Chemodynamic Therapeutic Nanoplatform with Activatable NIR-II Ratiometric Fluorescence for Self-Evaluating Fenton Reactivity

Real-time evaluation of the Fenton reactivity of chemodynamic therapy (CDT) agents is critical for developing effective CDT agents. However, the development of CDT agents capable of self-evaluating Fenton reactivity remains challenging. Herein, using ·OH as an indicator of Fenton reaction, we report a CDT nanoplatform, DCNP@FM-Fe2+-PEG (DFFP), which integrates a ·OH-activatable NIR-II ratiometric fluorescent nanoprobe and a Fenton agent (Fe2+), for self-evaluating Fenton reactivity. DFFP can induce cell apoptosis by converting intracellular H2O2 into ·OH and depleting GSH. In the presence of ·OH, NIR-II fluorescence signal of DFFP at 1050 nm under 808 nm excitation (F1050Em,808Ex) would be enhanced, while its fluorescence signal at 1550 nm under 980 nm excitation (F1550Em,980Ex) remained stable. DFFP was able to self-evaluate its Fenton reactivity by ·OH-activatable F1050Em,808Ex/F1550Em,980Ex signal, and it exhibited excellent anticancer effect. This strategy provides a new approach to construct CDT agents capable of self-evaluating the Fenton reactivity in real time.