MNPs@anionic MOFs/ERGO with the size selectivity for the electrochemical determination of H2O2 released from living cells

Herein, the ternary composites, ultrasmall metal nanoparticles encapsulated in the anionic metal-organic frameworks/electrochemically reduced graphene oxide (MNPs@Y-1, 4-NDC-MOF/ERGO, M = Ag, Cu) are constructed by a cationic exchange strategy and an electrochemical reduction process for the electrochemical determination of H 2 O 2 . Both AgNPs@Y-1, 4-NDC-MOF/ERGO and CuNPs@Y-1, 4-NDC-MOF/ERGO display excellent electrocatalytic activity toward H 2 O 2 , but the former is superior to the latter. Such a difference in electrocatalytic activity can be explained by the characterization measurements, and the results manifest MNPs@Y-1, 4-NDC-MOF/ERGO (M = Ag, Cu) electrocatalysts have subequal MNPs sizes and electrochemical surface areas, but different electron transfer rate constants. The AgNPs@Y-1, 4-NDC-MOF/ERGO sensor shows a linear detection range from 4 to 11,000 μM with the detection limit of 0.18 μM. Moreover, MNPs@Y-1, 4-NDC-MOF/ERGO (M = Ag, Cu) exhibit excellent anti-interference performance and can be used for the detection of H 2 O 2 released from living cells. The proposed sensor takes full advantage of the catalytic property of MNPs, the size selectivity of Y-1, 4-NDC-MOF, and the fast electron transport effect of ERGO. Thus, the MNPs@Y-1, 4-NDC-MOF/ERGO/GCE (M = Ag, Cu) can be utilized to detect oxidase activities by monitoring H 2 O 2 produced in the presence of substrate and oxidase, and it is expected that composites with the molecular sieving effect and catalytic activity can be widely applied for catalysis, biomedicine , and biosensing fields.