Controlled Synthesis of the FeB Nanometallic Glasses with Stronger Electron Donating Capability to Activate Molecular Oxygen for the Enhanced Ferroptosis Therapy.

Considering the strong electron-donating ability and the superior biocompatibility, the integration of zero-valent iron nanostructure Fe ⁰ (electron-reservoir) and zero-valent boron nanostructure B ⁰ offers great promise for fabricating novel ferroptosis nanoagents. Nevertheless, the controlled and facile synthesis of alloyed Fe ⁰ and B ⁰ nanostructure-FeB nanometallic glasses (NMGs) has remained a long-standing challenge. Herein, a complexion-reduction strategy is proposed for the controlled synthesis of FeB NMGs with greater electron donating capacity to activate the molecular oxygen for improved ferroptosis therapy. In-depth mechanism reveales that the complexion-reduction strategy effectively prevent the long-range diffusion of Fe ⁰ , resulting in the amorphous alloyed Fe ⁰ and B ⁰ nanostructure-FeB nanoparticles (FeB NPs). The FeB NPs display stronger electron donating capability and electron transfer rate 9.4 times higher than that of the Fe ⁰ NPs, which effectively activate the molecular oxygen to produce ∙O ₂ ^- , H ₂ O ₂ and ∙OH. The in vitro cellular experiments confirm the FeB-ss-SiO₂ NPs (encapsulation with SiO ₂ outlayer containing -S-S- bonds) demonstrates the enhanced ferroptosis. The tumor-bearing mice models shows that FeB-ss-SiO₂ NPs exhibited superior biocompatibility and tumor inhibition effect (inhibition rate of 73%), which improve the overall survival rate for 30 days post-treatment. This study will provide an innovative way to design therapeutic nanoagents for cancer treatments.
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