title: A "turn-on" fluorescent copper biosensor based on DNA cleavage-dependent graphene-quenched DNAzyme.
abstract: A novel and promising "turn-on" fluorescent Cu(2+) biosensor is designed based on graphene-DNAzyme catalytic beacon. Due to the essential surface and quenching properties of two-dimensional graphene, it can function as both "scaffold" and "quencher" of the Cu(2+)-dependent DNAzyme, facilitating the formation of self-assembled graphene-quenched DNAzyme complex. However, Cu(2+)-induced catalytic reaction disturbs the graphene-DNAzyme conformation, which will produce internal DNA cleavage-dependent effect. In this case, the quenched fluorescence in graphene-DNAzyme is quickly recovered to a large extent in 15 min. Compared with common DNAzyme-based sensors, the presented graphene-based catalytic beacon greatly improves the signal-to-background ratio, hence increasing the sensitivity (LOD=0.365 nM). Furthermore, the controllable DNA cleavage reaction provides an original and alternative internal method to regulate the interaction between graphene and DNA relative to the previous external sequence-specific hybridization-dependent regulation, which will open new opportunities for nucleic studies and sensing applications in the future.
authors.affiliation: Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education, China), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China.
authors.forename: Meng
authors.initials: M
authors.lastname: Liu
authors.forename: Huimin
authors.initials: H
authors.lastname: Zhao
authors.forename: Shuo
authors.initials: S
authors.lastname: Chen
authors.forename: Hongtao
authors.initials: H
authors.lastname: Yu
authors.forename: Yaobin
authors.initials: Y
authors.lastname: Zhang
authors.forename: Xie
authors.initials: X
authors.lastname: Quan
mesh_terms: D015374:Biosensing Techniques / Q000379:methods* / Q000706:statistics & numerical data; D003300:Copper / Q000032:analysis*; D004247:DNA; D053837:DNA Cleavage; D021881:DNA, Catalytic / Q000737:chemistry; D005453:Fluorescence; D006108:Graphite; D008958:Models, Molecular; D014874:Water Pollutants, Chemical / Q000032:analysis; D014881:Water Supply / Q000032:analysis
chemical_list: D021881:DNA, Catalytic; D014874:Water Pollutants, Chemical; D006108:Graphite; D003300:Copper; D004247:DNA