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Planar intercalated copper (II) complex molecule as small molecule enzyme mimic combined with Fe3O4 nanozyme for bienzyme synergistic catalysis applied to the microRNA biosensor
- Tian, Liang, Qi, Jinxu, Oderinde, Olayinka, Yao, Chen, Song, Wei, Wang, Yihong
- Biosensors & bioelectronics 2018 v.110 pp. 110-117
- bioassays, biosensors, catalytic activity, copper, electrochemistry, fluorescent dyes, hybridization chain reaction, iron oxides, magnetic fields, microRNA
- Enzyme mimics have been developed for bioassay of nucleic acids, with some of them involving complicated labeling. Herein, we report a label-free bioassay for ultrasensitive electronic determination of microRNA at an ultralow concentration based on target-triggered long-range self-assembly DNA-based hybridization chain reaction (HCR) protocol coupled with bienzyme mimics synergistic catalysis strategy. In this work, a planar intercalation molecule, copper (II) complex, is applied for the first time as a small molecule enzyme mimic as well as intercalation molecule in microRNA biosensor for signal amplification. Fe3O4 nanozyme were used as a separate and enriched target under magnetic field, and also in combination with HCR protocol detected in 3,3’,5,5’-tetramethylbenzidine+hydrogen peroxide (TMB+H2O2) system to improve the sensitivity of the biosensor. Under optimal conditions, these strategies present good electrochemical behaviors for the detection of microRNA with a wide range from 100 aM to 100 nM and at relatively low detection limit of 33 aM This remarkable sensitivity can make this proposed approach a promising scheme for development of next-generation microRNA sensors without the need of enzyme labeling or fluorophore labeling.