title: An electrochemical microRNAs biosensor with the signal amplification of alkaline phosphatase and electrochemical-chemical-chemical redox cycling.
abstract: MicroRNAs (MiRNAs) have been regarded as clinically important biomarkers and drug discovery targets. In this work, we reported a simple and ultrasensitive electrochemical method for miRNAs detection based on single enzyme amplification and electrochemical-chemical-chemical (ECC) redox cycling. Specifically, upon contact with the target miRNAs, the hairpin structure of biotinylated DNA immobilized on gold electrode was destroyed and the biotin group in DNA was forced away from the electrode surface, allowing for the coupling of streptavidin-conjugated alkaline phosphatase (SA-ALP). Then, ascorbic acid (AA, the enzymatic product of ALP) triggered the ECC redox cycling with ferrocene methanol (FcM) and tris(2-carboxyethyl)phosphine (TCEP) as the redox mediator and the chemical reducing reagent, respectively. The method was more sensitive than that with horseradish peroxidase (HRP) or glucose oxidase (GOx) triggered recycling since one ALP molecule captured by one target miRNA molecule promoted the production of thousands of AA. Analytical merits (e.g., detection limit, dynamic range, specificity, regeneration and reproducibility) were evaluated. The feasibility of the method for analysis of miRNA-21 in human serum has also been demonstrated.
authors.affiliation: College of Chemistry and Chemical Engineering, Anyang Normal University, Anyang, Henan 455000, People's Republic of China.
authors.forename: Ning
authors.initials: N
authors.lastname: Xia
authors.affiliation: College of Chemistry and Chemical Engineering, Anyang Normal University, Anyang, Henan 455000, People's Republic of China.
authors.forename: Youjuan
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: College of Chemistry and Chemical Engineering, Anyang Normal University, Anyang, Henan 455000, People's Republic of China.
authors.forename: Xin
authors.initials: X
authors.lastname: Wei
authors.affiliation: College of Chemistry and Chemical Engineering, Anyang Normal University, Anyang, Henan 455000, People's Republic of China.
authors.forename: Yaping
authors.initials: Y
authors.lastname: Huang
authors.affiliation: College of Chemistry and Chemical Engineering, Anyang Normal University, Anyang, Henan 455000, People's Republic of China. Electronic address: liulin@aynu.edu.cn.
authors.forename: Lin
authors.initials: L
authors.lastname: Liu
mesh_terms: D000469:Alkaline Phosphatase / Q000737:chemistry / Q000378:metabolism; D001205:Ascorbic Acid / Q000378:metabolism; D015374:Biosensing Techniques / Q000295:instrumentation / Q000379:methods*; D001710:Biotin / Q000737:chemistry; D055664:Electrochemical Techniques / Q000295:instrumentation / Q000379:methods*; D004566:Electrodes; D004867:Equipment Design; D006046:Gold / Q000737:chemistry; D006801:Humans; D061925:Immobilized Nucleic Acids / Q000737:chemistry; D057230:Limit of Detection; D035683:MicroRNAs / Q000032:analysis / Q000097:blood*; D010084:Oxidation-Reduction; D015203:Reproducibility of Results; D019809:Streptavidin / Q000737:chemistry
chemical_list: D061925:Immobilized Nucleic Acids; C524940:MIRN21 microRNA, human; D035683:MicroRNAs; D001710:Biotin; D006046:Gold; D019809:Streptavidin; D000469:Alkaline Phosphatase; D001205:Ascorbic Acid
keywords: Alkaline phosphatase; Electrochemical biosensors; MicroRNAs; Redox cycling; Single enzyme amplification