Siqi Chen,Tingting Li,Donglian Deng,Yibing Ji,Ruijun Li
This work innovatively integrated the peroxidase-mimicking activity and red emission property of Fe@PCN-222 framework, designed a cascade reaction system for dual-mode glucose sensing. The Fe 3+ doping significantly improved the catalytic activity of Fe@PCN-222 that can oxidize the substrate o -phenylenediamine (OPD) to generate diminophenazine (DAP) with emission at 566 nm in the presence of H 2 O 2 . Similarly, the Fe@PCN-222 was used to catalyze the colorless TMB to produce blue oxidized TMB (oxTMB) showed absorption at 652 nm. When coupled with glucose oxidase (GOx), the linear ranges of ratiometric fluorescence mode and colorimetric mode for glucose sensing were 1–100 and 10–300 μM, respectively. And the limits of detection (LOD) of 0.78 and 2.41 μM for two modes were obtained, respectively. In addition, the practicability of Fe@PCN-222 nanozyme-based cascade reaction system for detection of glucose in human serum and saliva samples was successfully investigated. It is of great importance to integrate more functions into one skeleton to achieve dual-mode and optimal-performance sensing for expanding potential applications.
Yijin Shu,Qiao Ye,Jingwen Tan,Hui Lv,Zhiyin Liu,Qijie Mo
Metal–organic frameworks (MOFs) and their derivatives are emerging biosensing platforms due to their rational structural optimization. Herein, several metalloporphyrin–Porous Coordinated Network-222 (M-PCN-222) are developed for composition-dependent hydrogen peroxide (H2O2) sensing. A typical colorimetric sensing method (via a 3,3′,5,5′-tetramethylbenzidine-induced allochroic reaction) is employed to investigate the intrinsic peroxidase activity of M-PCN-222 (M = Mn, Fe, Co, and Ni). Fe-PCN-222 affords high sensitivity, good selectivity, robust stability, and a widely applicable concentration range. Theoretical investigations of active sites reveal that such different performances stem from the OH* binding on the M-PCN-222 surface. In addition, the adsorption energy of OH* on Fe-PCN-222 is similar to that of natural horseradish peroxidase. Molecular dynamics simulations are performed on Fe-PCN-222 nanorods to study the catalytic process of H2O2 based on their abundant micropores and mesopores. The obtained results suggest that the porphyrinic Fe-PCN-222 nanorod-based colorimetric sensing of H2O2 has great potential in catalysis, biosensors, and food industries.
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