Research on metal-organic framework (MOF)-based non-enzymatic glucose sensors usually ignores the impact of the surface reconstruction degree of MOF on the activity of catalyzing glucose oxidation. In this work, we choose zeolitic imidazolate framework-67 (ZIF-67), which is commonly used in glucose sensing, as a representative to investigate the influence of reconstruction degree on its structure and glucose catalytic performance. By employing the electrochemical activation strategy, the activity of ZIF-67 in catalyzing glucose gradually increased with the prolongation of the activation time, reaching the optimum after 2 h activation. The detection sensitivity of the activated ZIF-67 was 19 times higher than that of the initial ZIF-67, and the limit of detection (LOD) was lowered from 7 to 0.4 μM. Our findings demonstrate that the oxidation degree of ZIF-67 deepened rapidly with continuously activation and was basically reconstructed to CoOOH after 2 h activation, accompanied by a morphological change from cuboctahedral to flower-like. Simultaneously, theoretical investigation revealed that ZIF-67 is not suitable as a stable glucose sensor electrode since the adsorbed glucose molecules hasten the dissociation of ligands and the breaking of Co–N bond in ZIF-67. Therefore, our work has important implications for the rational design of next-generation MOF-based glucose sensors.

This article presents a high-speed distributed vibration sensing based on Mach-Zehnder-OTDR (optical time-domain reflectometry). Ultra-weak fiber Bragg gratings (UWFBG), whose backward light intensity is 2-4 orders of magnitude higher than that of Rayleigh scattering, are used as the reflection markers. A medium-coherence laser can substitute conventional narrow bandwidth source to achieve an excellent performance of distributed vibration sensing since our unbalanced interferometer matches the interval of UWFBGs. The 3m of spatial resolution of coherent detection and multiple simultaneous vibration sources locating can be realized based on OTDR. The enhanced signal to noise ratio (SNR) enables fast detection of distributed vibration without averaging. The fastest vibration of 25kHz and the slowest vibration of 10Hz can be detected with our system successfully, and the linearity is 0.9896 with a maximum deviation of 3.46nƐ.