X-ray-triggered fenton-like nanocomposites for passive-activation and non-spontaneous chemodynamic therapy

Currently, many studies focused on the TME-regulating strategies to address the unsatisfactory therapeutic effect of single chemodynamic therapy (CDT). However, most of TME-regulating strategies were nonspecific, the CDT agents with spontaneous CDT activity would result in augmented killing effect not only in tumor but also in normal tissues. Furthermore, CDT efficiency was subject to attenuation due to the gradually exhausted active sites in CDT agents. Herein, the passive-activation and non-spontaneous CDT strategy was proposed by constructing a completely X-ray-triggered CDT agent (F-SCNPs) to target the therapeutic dilemma between the augmented CDT efficacy and high tumor specificity. In this study, the designed F-SCNPs can launch Fe²⁺ sites generation to initiate CDT activity only when they were exposed to X-ray, which were totally different from the traditional CDT agents including other stimuli-responsive CDT agents that always spontaneously exert CDT activity no matter they had accepted the stimuli or not. The X-ray-activated feature of F-SCNPs endowed their tumor specificity with less affect by nonspecific TME-regulating strategies. Meanwhile, X-ray can promote the Fe²⁺/Fe³⁺ cycling of F-SCNPs to enhance the •OH yield. This X-ray-mediated nanosystem with remarkable synergistic therapy of CDT and radiotherapy provided a promising avenue for high-efficiency and precise cancer treatments.