title: Combining padlock exponential rolling circle amplification with CoFe2O4magnetic nanoparticles for microRNA detection by nanoelectrocatalysis without a substrate.
abstract: In this report, an ultrasensitive electrochemical biosensor for miR-21 detection was designed on the basis of a padlock exponential rolling circle amplification (P-ERCA) assay and CoFe2O4magnetic nanoparticles (CoFe2O4MNPs) by nanoelectrocatalysis without a substrate for signal amplification. Here, to improve catalytic efficiency, nanocatalyst (CoFe2O4MNPs) and redox molecule (Tb) were co-immobilized onto the graphene (Gra) surface and formed Au@CoFe2O4/Tb-Gra probe. The obtained probe exhibits high-performance Tb catalysis by reducing the interaction distance between CoFe2O4MNPs and Tb, and importantly, the detection sensitivity is significantly improved even in the absence of substrate (H2O2). Simultaneously, to further improve the sensitivity and specificity of the biosensor, P-ERCA assay was introduced. After multiple polymerization and nicking reactions, plenty of P-ERCA amplification product was produced and circular exponential signal amplification was achieved, giving an extreme sensitivity for miR-21 assay. The as-prepared biosensor shows a wide dynamic range of 1 fM to 2 nM with a low detection limit of 0.3 fM for miR-21 detection and exhibits high specificity and sensitivity.
authors.affiliation: Shaanxi Provincial Key Laboratory of Biotechnology, Key Laboratory of Resource Biology and Biotechnology in Western China (Ministry of Education), Northwest University, Xi'an 710069, PR China.
authors.forename: Nan
authors.initials: N
authors.lastname: Yu
authors.affiliation: Key Lab of Synthetic and Natural Functional Molecule Chemistry of Ministry of Education, College of Chemistry and Materials Science, Northwest University, Xi'an, Shaanxi 710127, PR China.
authors.forename: Zhen
authors.initials: Z
authors.lastname: Wang
authors.affiliation: Shaanxi Provincial Key Laboratory of Biotechnology, Key Laboratory of Resource Biology and Biotechnology in Western China (Ministry of Education), Northwest University, Xi'an 710069, PR China.
authors.forename: Chaochen
authors.initials: C
authors.lastname: Wang
authors.affiliation: Key Lab of Synthetic and Natural Functional Molecule Chemistry of Ministry of Education, College of Chemistry and Materials Science, Northwest University, Xi'an, Shaanxi 710127, PR China. Electronic address: hanjing@nwu.edu.cn.
authors.forename: Jing
authors.initials: J
authors.lastname: Han
authors.affiliation: Shaanxi Provincial Key Laboratory of Biotechnology, Key Laboratory of Resource Biology and Biotechnology in Western China (Ministry of Education), Northwest University, Xi'an 710069, PR China. Electronic address: buhy@nwu.edu.cn.
authors.forename: Huaiyu
authors.initials: H
authors.lastname: Bu
mesh_terms: D015374:Biosensing Techniques / Q000379:methods*; D002138:Calibration; D002384:Catalysis; D003035:Cobalt / Q000737:chemistry*; D004563:Electrochemistry; D005290:Ferric Compounds / Q000737:chemistry*; D059346:Magnets / Q000737:chemistry*; D035683:MicroRNAs / Q000037:antagonists & inhibitors* / Q000737:chemistry; D053758:Nanoparticles / Q000737:chemistry*; D036103:Nanotechnology / Q000379:methods*
chemical_list: D005290:Ferric Compounds; D035683:MicroRNAs; C569492:cobalt ferrite; D003035:Cobalt
keywords: CoFe(2)O(4) MNPs; Electrochemical biosensor; MicroRNA; Nanoelectrocatalysis; P-ERCA assay