Ratiometric electrochemical probes are vital for reliable sensing but often suffer from complex preparation, reference molecule leakage, and single function. To address these limitations, this study reports a flower-like Cu-doped zeolite imidazolate framework (Zn 0.5 /Cu 0.5 /Co-ZIF) prepared at room temperature via simple stirring. This material acts as both an electrode material and a robust ratiometric probe for detecting catechol (CC) and acetaminophen (AP). Compared with pristine Zn/Co-ZIF, Cu doping confers several advantages: transforming lamellar Zn/Co-ZIF into a flower-like structure for enhanced electron and mass transfer; significantly improving redox current of CC/AP for high sensitivity; and generating a stable Cu-based redox signal as an internal reference, improving accuracy. The sensor achieved wide linear ranges (CC: 0.5–150 μM; AP: 0.2–300 μM) and low detection limits (CC: 0.12 μM; AP: 0.04 μM) for determination of phenol compounds. Compared to single-signal assay, the ratiometric approach showed lower RSDs and superior linear correlations. The sensor also achieved satisfactory simultaneous detection of CC and AP, along with accurate quantification in lake water samples. This work presents a facile strategy for a MOF based reference probe, offering a promising platform for stable and accurate ratiometric electrochemical sensors.
Ferroptosis and cuproptosis are emerging modes of programmed cell death and have been increasingly used to eliminate tumor cells. However, converting ferroptosis/cuproptosis into effective treatments is challenging because of the inherent antioxidant and plasma membrane repair systems and inefficient copper ion delivery. Herein, an engineered doping method is developed to encapsulate ZnO 2 with Cu 2+ -doped ZIF-8 and modify the surface by transferrin (Tf). In the resulting ZnO 2 @Cu/ZIF-8-Tf nanosystem, Tf specifically binds to transferrin receptors for targeting and aggregation. In the tumor microenvironment, Cu 2+ /Fe 3+ is released from the nanosystem and reacted with glutathione (GSH) to produce Cu + /Fe 2+ . Excessive accumulation of Cu + interfered with the tricarboxylic acid cycle and induced coproptosis. Furthermore, the additional Fe 2+ caused iron overload and enhanced ferroptosis. ZnO 2 supplied hydrogen peroxide to mediate the overproduction of reactive oxygen species (ROS). Moreover, the depletion of GSH deactivated glutathione peroxidase 4 (GPX4) and inhibited the system X c − -GSH-GPX4 pathway, and the amplified ROS triggered lipid peroxidation and reprogrammed lipid metabolism, causing malfunctioning of both antioxidant and membrane repair systems. In summary, the ferroptosis/cuproptosis pathways are activated at multiple levels in the ZnO 2 @Cu/ZIF-8-Tf nanosystem, which ensures its outstanding antitumor effect.
Hui Yao,Wan-ting Zhang,Ting-yu Yan,Xiao-qin Li,Xiao-feng Wang
Metal-Organic Frameworks (MOFs) are promising materials in electrochemical sensor. Herein, Cu-doped zeolitic imidazolate framework (ZIF) was synthesized by hydrothermal method. The prepared composite was characterized by XRD, FTIR and SEM. Then the material was modified onto the surface of glass carbon electrode (GCE) with chitosan(CHIT) and Cytochrome C (cyt c ). The modified electrode showed good electrochemical activity toward the reduction of hydrogen peroxide (H 2 O 2 ). Under optimized conditions, the linear response of the sensor to H 2 O 2 ranges from 10～5200 μM, with a detection limit of 3.7 μM (S/N=3). Finally, the sensor was successfully applied to determine H 2 O 2 in water samples. Thus, the Cu-doped ZIF material has great potential for applications in electrochemical sensors.
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