Xue-Liang Liu,Mengdi Yan,Zhi-guo Chen,Bingxin Zhang,Ningcong Yao,Shan Zhao,Xiaoxia Zhao,Tao Zhang,Guangfan Hai
In this paper, we reported a coumarin-based fluorescent probe for selective detection of H 2 O 2 /SO 2 derivatives via ICT process. To the best of our knowledge, it was few reported with the same probe to enable visual detection of H 2 O 2 /SO 2 derivatives in vivo and in vitro. H 2 O 2 and SO 3 2− were selectively sensed over other analytes, and the probe displayed 20-fold and 220-fold relative fluorescence intensity respectively, as well as the good linear relationship and the excellent detection limits of 2.7 * 10 3 nM and 19.3 nM. Furthermore, the probe was successfully used for fluorescence imaging of the HeLa cells and the mice to monitor exogenous and endogenous H 2 O 2 and SO 3 2− , suggesting its potential biomedical application for investigation and detection the intermediate indicator of oxidative stress in vitro and in vivo.
Single-atom nanozymes (SAzymes), with individually isolated metal atom as active sites, have shown tremendous potential as enzyme-based drugs for enzymatic therapy. However, using SAzymes in tumor theranostics remains challenging because of deficient enzymatic activity and insufficient endogenous H2O2. We develop an external-field-enhanced catalysis by an atom-level engineered FeN4-centered nanozyme (FeN4-SAzyme) for radio-enzymatic therapy. This FeN4-SAzyme exhibits peroxidase-like activity capable of catalyzing H2O2 into hydroxyl radicals and converting single-site FeII species to FeIII for subsequent glutathione oxidase-like activity. Density functional theory calculations are used to rationalize the origin of the single-site self-cascade enzymatic activity. Importantly, using X-rays can improve the overall single-site cascade enzymatic reaction process via promoting the conversion frequency of FeII/FeIII. As a H2O2 producer, natural glucose oxidase is further decorated onto the surface of FeN4-SAzyme to yield the final construct GOD@FeN4-SAzyme. The resulting GOD@FeN4-SAzyme not only supplies in situ H2O2 to continuously produce highly toxic hydroxyl radicals but also induces the localized deposition of radiation dose, subsequently inducing intensive apoptosis and ferroptosis in vitro. Such a synergistic effect of radiotherapy and self-cascade enzymatic therapy allows for improved tumor growth inhibition with minimal side effects in vivo. Collectively, this work demonstrates the introduction of external fields to enhance enzyme-like performance of nanozymes without changing their properties and highlights a robust therapeutic capable of self-supplying H2O2 and amplifying self-cascade reactions to address the limitations of enzymatic treatment.
Wei Li,Daomei Chen,Chungang Min,Xiaoqian Ma,Xikun Yang,Jiaqiang Wang
The intervention of endogenous H 2 O 2 via nanozymes provides a potential antitumor-specific therapy; however, the role of the nanozyme structure in relation to the selective decomposition of H 2 O 2 to hydroxyl radicals (•OH) is yet to be fully understood, which limits the development of this therapeutic approaches. Herein, an iron single-atom nanozyme (Fe─N 2 Cl 2 ─C SAzyme) is reported, which is prepared through precise Fe─Cl coordination based on the construction of a characteristic Fe-containing molecule. Fe─N 2 Cl 2 ─C exhibits efficient catalytic H 2 O 2 decomposition (2.19 × 10 6 m m −1 s −1 ), which is the highest among reported SAzymes. More importantly, it is found that H 2 O 2 selectively decomposed into •OH on the Fe─N 2 Cl 2 ─C surface, which is attributable to the d orbitals of the Fe active center matching the O-2 p electrons of the adsorbed hydroxide (*OH) intermediate. Fe─N 2 Cl 2 ─C is strongly cytotoxic toward a variety of cancer-cell lines in vitro but not to normal cells. Furthermore, Fe─N 2 Cl 2 ─C shows an outstanding specific therapeutic effect in vivo; it efficiently destroys solid malignant tumors without injuring normal tissue. Altogether, these findings highlight the selective catalytic decomposition of H 2 O 2 to •OH, which is achieved by engineering the active center on the atomic level, thereby providing an avenue for the development of specific nanomedicines with efficient antitumor activities.
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