Henan Normal University

Chemodynamic therapy (CDT) faces critical challenges including low reactive oxygen species (ROS) generation efficiency, short-lived oxidative stress, antioxidative tumor microenvironment (TME), and other limiting factors. Although nanozymes demonstrate remarkable ROS-generating capacity, the influence of electron transfer mechanisms on nanozyme activity remains rarely reported. Herein, a double-layer hollow nanozyme Cu_2-x/CeO₂@ICG (CCI) with multiple catalytic activities was designed to enhance the electron transfer between Cu and CeO₂ through its unique structure, activating peroxidase (POD), oxidase (OXD), and catalase (CAT) enzyme-like activities for TME-responsive cascade catalysis. Further density functional theory (DFT) calculations reconfirm the outstanding catalytic activity. Experiments demonstrate that the CCI nanozyme significantly enhances the tumor therapeutic efficacy through the following mechanisms: (1) the distinctive double-layer hollow architecture with a higher volume specific surface area substantially enhances electron transfer, (2) the nanozyme, possessing POD- and OXD-like enzymatic activities, efficiently converts H₂O₂/O₂ into ·OH/·O₂^-, respectively. Meanwhile, the CAT-like activity alleviates tumor hypoxia, thereby enhancing both photodynamic therapy (PDT) efficacy and OXD-like activity, (3) Cu²⁺/Ce⁴⁺-mediated glutathione (GSH) depletion disrupts the ROS-antioxidant balance, and ROS levels in TME are further elevated, (4) the combination of photothermal therapy (PTT)/PDT and CDT achieves sustained ROS accumulation. This study provides a novel nanozyme catalytic strategy to overcome the limitations of traditional CDT, demonstrating the clinical potential of multimodal cascade therapy.

Seawater electrolysis is promising yet challenging, as the rapid multi-step deprotonation process of oxygen evolution reaction (OER), along with the Ca²⁺, Mg²⁺ ions, would deplete the accessible OH^- ions near the catalyst-electrolyte interface. Herein, we present the hexatantalate [Ta₆O₁₉]^8- ({Ta₆}), a robust H-bond acceptor (HA) to customize the interfacial H-bonds and charge transfer of the layered metal organic framework (MOF) electrocatalyst, for efficiency alkaline seawater OER. Experimental findings reveal that the {Ta₆} cluster reconstructs the H-bond networks both in the MOF interlayers and at the catalyst-electrolyte interface, liberating more free OH^- to penetrate the Helmholtz plane and adsorb onto the catalyst surface. The increased accessible OH^- deepens the partial reconstruction degree of the MOF into active components. Besides, the {Ta₆} cluster modulates the electronic configuration of Ni active sites in the MOF framework, enabling the synthesized R-MOF-Ta₆/NF electrocatalyst to achieve a low overpotential of 235 mV at a current density of 10 mA cm^-2. Moreover, the anion exchange membrane (AEM) electrolyzer utilizing the R-MOF-Ta₆/NF anode catalyst could operate 195 h at industrial current density (≥200 mA cm^-2). This study presents a neoteric strategy to enhance the performance of layered catalysts for seawater OER.

Rehmannia glutinosa roots produce a group of lipophilic bioactive components known as iridoid glycosides. However, the molecular mechanisms by which DNA methylation regulates the biosynthesis of iridoid glycosides in R. glutinosa remain unknown. Herein, the development of R. glutinosa roots and the content of iridoid glycosides in the Wenxian region were significantly higher than those in Xinxiang. Low methylation level contributed to the accumulation of iridoid glycosides and the expression of related enzyme genes. Demethylation promoted both roots growth and development, as well as the accumulation of iridoid glycosides. Up-regulated genes including aldehyde dehydrogenase (RgALDH13), 1-hydroxy-2-methyl-2-butenyl 4-diphosphate reductase (RgHDR1), geraniol 10-hydroxylases (RgG10H3 and RgG10H4), 1-deoxy-d-xylulose 5-phosphate reductoisomerase (RgDXR1), uroporphyrinogen decarboxylase (RgUPD1), and various transcription factors, collectively form the regulatory network for iridoid glycoside biosynthesis. Furthermore, the primary active region of the RgG10H4 promoter is located in the -164 bp region, where the RgMYB2 protein specifically binds to the TAACCA motif in the RgG10H4 promoter. Collectively, low DNA methylation enhances core gene expression, promoting iridoid glycoside accumulation, with RgMYB2-RgG10H4 positively regulating this process. The study provides new insights into the regulation of iridoid glycosides biosynthesis in plants by DNA methylation.