title: A rapid and visual turn-off sensor for detecting copper (II) ion based on DNAzyme coupled with HCR-based HRP concatemers.
abstract: To solve the requirement of on-site, rapid, and visual detection of copper (II) (Cu2+) in aqueous solution, a turn-off sensor for detecting copper (II) ion was developed based on Cu2+-dependent DNAzyme as the recognition element and hybridization chain reaction (HCR)-based horseradish peroxidase (HRP) concatemers as the signal amplifier and the signal report element. The detection unit, which was composed of the immobilized Cu2+-dependent DNAzyme coupled with HCR-based HRP concatemers via Waston-Crick base pairing, could catalyze hydrogen peroxide (H2O2) via TMB, generating obvious green color and turning yellow after sulfuric acid termination with optical absorption at 450 nm. Upon Cu2+addition, the substrate strand of the Cu2+-dependent DNAzyme concatenated with the HCR-based HRP complex was irreversibly cleaved, efficiently causing dramatic reduction of the detection signal. Under optimal conditions, the detection signal decreased with the concentration of Cu2+in 5 min, exhibiting a linear calibration from 0.05 to 3 μM with a detection limit of 8 nM. The sensor also displayed a high selectivity for Cu2+given the specificity and anti-interference of the detection unit, and this system was applicable for monitoring Cu2+in real water samples. Generally speaking, the proposed sensor exhibits good potential in environment surveys.
authors.affiliation: Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Food Science &Nutritional Engineering, China Agricultural University, Beijing 100083, China.|Beijing Laboratory for Food Quality and Safety, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China.
authors.forename: Wentao
authors.initials: W
authors.lastname: Xu
authors.affiliation: Beijing Laboratory for Food Quality and Safety, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China.
authors.forename: Jingjing
authors.initials: J
authors.lastname: Tian
authors.affiliation: Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Food Science &Nutritional Engineering, China Agricultural University, Beijing 100083, China.
authors.forename: Yunbo
authors.initials: Y
authors.lastname: Luo
authors.affiliation: Beijing Laboratory for Food Quality and Safety, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China.
authors.forename: Longjiao
authors.initials: L
authors.lastname: Zhu
authors.affiliation: Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Food Science &Nutritional Engineering, China Agricultural University, Beijing 100083, China.|Beijing Laboratory for Food Quality and Safety, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China.
authors.forename: Kunlun
authors.initials: K
authors.lastname: Huang
mesh_terms: D015374:Biosensing Techniques / Q000379:methods*; D003300:Copper / Q000032:analysis*; D021881:DNA, Catalytic / Q000378:metabolism*; D006735:Horseradish Peroxidase / Q000378:metabolism*; D009693:Nucleic Acid Hybridization; D012680:Sensitivity and Specificity; D013997:Time Factors; D014131:Trace Elements / Q000032:analysis*
chemical_list: D021881:DNA, Catalytic; D014131:Trace Elements; D003300:Copper; D006735:Horseradish Peroxidase