The insufficient exposure sites and active site competition of multienzyme are the two main factors to hinder its therapeutic effect. Here, a phase-junction nanomaterial (amorphous-crystalline Cux S-Ag2 S) is designed and prepared through a simple room temperature ion-exchange process. A small amount of Ag+ is added into Cu7 S4 nanocrystals, which transforms Cu7 S4 into amorphous phased Cux S and produces crystalline Ag2 S simultaneously. In this structure, the overhanging bonds on the amorphous Cux S surface provide abundant active sites for optimizing the therapeutic activity. Meanwhile, the amorphous state enhances the photothermal effect through non-radiative relaxation, and due to its low thermal resistance, phase-junction Cux S-Ag2 S forms a significant temperature gradient to unlock the optimized thermo-electrodynamic therapy. Furthermore, benefiting from the high asymmetry of the amorphous state, the material forms a spin-polarized state that can effectively inhibit electron-hole recombination. In this way, the thermoelectric effect can facilitate the enzyme-catalyzed cycle by providing electrons and holes, enabling an enhanced coupling of thermoelectric therapy with multienzyme activity, which induces excellent anti-tumor performance. More importantly, the catalytic process simulated by density-functional theory proves that Ag+ alleviates the burden on the Cu sites through favorable adsorption of O2 and prevents active site competition.
Keywords: amorphous materials; enzyme catalysis; phase-junction; photothermoelectric therapy; site competition.
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