title: DNA transducer-triggered signal switch for visual colorimetric bioanalysis.
abstract: A simple and versatile colorimetric biosensor has been developed for sensitive and specific detection of a wide range of biomolecules, such as oligonucleotides and aptamer-recognized targets. Combining the signal transducer and catalyzed hairpin assembly (CHA)-based signal amplification, the target DNA binds with the hairpin DNA to form a new nucleic acid sequence and creates a toehold in the transducer for initiating the recycle amplification reaction of CHA. The catalyzed assembly process produces a large amount of G-rich DNA. In the presence of hemin, the G-rich DNA forms G-quadruplex/hemin complex and mimic horseradish peroxidase activity, which catalyzes a colorimetric reaction. Under optimal conditions, the calibration curve of synthetic target DNA has good linearity from 50 pM to 200 nM with a detection limit of 32 pM. This strategy has been successfully applied to detect S. pneumoniae as low as 156 CFU mL(-1), and shows a good specificity against closely related streptococci and major pathogenic bacteria. In addition, the developed method enables successful visual analysis of S. pneumoniae in clinical samples by the naked eye. Importantly, this method demonstrates excellent assay versatility for sensitively detecting oligonucleotides or aptamer-recognized targets.
authors.affiliation: Ministry of Education Key Laboratory of Child Development and Disorders; Key Laboratory of Pediatrics in Chongqing, CSTC2009CA5002; Chongqing International Science and Technology Cooperation Center for Child Development and Disorders; Department of Clinical laboratory, Children's Hospital of Chongqing Medical University, Chongqing 400014, PR China.
authors.forename: Wenhong
authors.initials: W
authors.lastname: Chen
authors.affiliation: 1] Ministry of Education Key Laboratory of Child Development and Disorders; Key Laboratory of Pediatrics in Chongqing, CSTC2009CA5002; Chongqing International Science and Technology Cooperation Center for Child Development and Disorders; Department of Clinical laboratory, Children's Hospital of Chongqing Medical University, Chongqing 400014, PR China [2] Key Laboratory of Clinical Laboratory Diagnostics (Ministry of Education), College of Laboratory Medicine, Chongqing Medical University, Chongqing 400016, PR China.
authors.forename: Yurong
authors.initials: Y
authors.lastname: Yan
authors.affiliation: Key Laboratory of Clinical Laboratory Diagnostics (Ministry of Education), College of Laboratory Medicine, Chongqing Medical University, Chongqing 400016, PR China.
authors.forename: Ye
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Clinical Laboratory Diagnostics (Ministry of Education), College of Laboratory Medicine, Chongqing Medical University, Chongqing 400016, PR China.
authors.forename: Xuemei
authors.initials: X
authors.lastname: Zhang
authors.affiliation: 1] Ministry of Education Key Laboratory of Child Development and Disorders; Key Laboratory of Pediatrics in Chongqing, CSTC2009CA5002; Chongqing International Science and Technology Cooperation Center for Child Development and Disorders; Department of Clinical laboratory, Children's Hospital of Chongqing Medical University, Chongqing 400014, PR China [2] Key Laboratory of Clinical Laboratory Diagnostics (Ministry of Education), College of Laboratory Medicine, Chongqing Medical University, Chongqing 400016, PR China.
authors.forename: Yibing
authors.initials: Y
authors.lastname: Yin
authors.affiliation: 1] Ministry of Education Key Laboratory of Child Development and Disorders; Key Laboratory of Pediatrics in Chongqing, CSTC2009CA5002; Chongqing International Science and Technology Cooperation Center for Child Development and Disorders; Department of Clinical laboratory, Children's Hospital of Chongqing Medical University, Chongqing 400014, PR China [2] Key Laboratory of Clinical Laboratory Diagnostics (Ministry of Education), College of Laboratory Medicine, Chongqing Medical University, Chongqing 400016, PR China.
authors.forename: Shijia
authors.initials: S
authors.lastname: Ding
mesh_terms: D015374:Biosensing Techniques / Q000379:methods*; D003124:Colorimetry / Q000379:methods*; D004247:DNA / Q000737:chemistry*; D054856:G-Quadruplexes; D006801:Humans; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D004247:DNA