title: Label-free and ultrasensitive colorimetric detection of DNA based on target-triggered quadratic amplification strategy.
abstract: Highly sensitive detection of DNA plays a crucial role in biomedical research and clinical diagnosis. Herein, we developed a simple, label-free, isothermal, and ultrasensitive colorimetric method for amplified detection of DNA on the basis of a new quadratic amplification strategy. With the presence of three ingeniously designed hairpin structures and Exonuclease III (Exo III), the target DNA can trigger two independent cycles of reactions: hairpin assembly reaction and Exo III cleavage reaction, which are designed to initiate target DNA recycling amplification and reporter DNA amplification, respectively. Therefore, the proposed method exhibits a high sensitivity toward target DNA with a detection limit of as low as 81 fM, and it can discriminate mismatched DNA from completely matched target DNA. Furthermore, this method could be used as a universal tool for the detection of various DNA sequences and might be further extended for the detection of aptamer-binding molecules.
authors.affiliation: Key Laboratory of Nuclear Medicine, Ministry of Health, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi, Jiangsu 214063, China. Electronic address: wuhao@jsinm.org.
authors.forename: Hao
authors.initials: H
authors.lastname: Wu
authors.affiliation: Key Laboratory of Nuclear Medicine, Ministry of Health, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi, Jiangsu 214063, China.
authors.forename: Yaling
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Key Laboratory of Nuclear Medicine, Ministry of Health, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi, Jiangsu 214063, China.
authors.forename: Hongyong
authors.initials: H
authors.lastname: Wang
authors.affiliation: Key Laboratory of Nuclear Medicine, Ministry of Health, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi, Jiangsu 214063, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Wu
authors.affiliation: Key Laboratory of Nuclear Medicine, Ministry of Health, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi, Jiangsu 214063, China.
authors.forename: Feifan
authors.initials: F
authors.lastname: Zhu
authors.affiliation: Key Laboratory of Nuclear Medicine, Ministry of Health, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi, Jiangsu 214063, China. Electronic address: zoupei@jsinm.org.
authors.forename: Pei
authors.initials: P
authors.lastname: Zou
mesh_terms: D001483:Base Sequence; D015374:Biosensing Techniques / Q000379:methods; D003124:Colorimetry / Q000379:methods*; D004247:DNA / Q000032:analysis* / Q000378:metabolism; D005090:Exodeoxyribonucleases / Q000378:metabolism; D054856:G-Quadruplexes; D057230:Limit of Detection; D021141:Nucleic Acid Amplification Techniques / Q000379:methods*
chemical_list: D004247:DNA; D005090:Exodeoxyribonucleases; C020133:exodeoxyribonuclease III
keywords: DNA detection; Exonuclease III; G-quadruplex/hemin DNAzyme; Quadratic amplification; Target-catalyzed hairpin assembly