title: Simple and highly selective detection of arsenite based on the assembly-induced fluorescence enhancement of DNA quantum dots.
abstract: Novel fluorescent DNA quantum dots (QDs) were synthesized by hydrothermal treatment of G-/T-rich ssDNA at relatively low reaction temperature. The obtained DNA QDs demonstrate unique optical properties, maintain the basic structure and biological activities of ssDNA precursors, which makes the DNA QDs able to specifically bind with arsenite, driving the (GT)29region suffer conformation evolution and form well-ordered assembly rather than random aggregations. We speculate that the strong inter-molecule interaction and efficient stacking of base pairs stiffen the assembly structure, block the nonradiative relaxation channels, populate the radiative decay, and thus making the assembly be highly emissive as a new fluorescence center. The arsenite-induced specific fluorescence enhancement facilitates DNA QDs as light-up probes for arsenite sensing. Under optimal conditions, a linear relationship between the increased fluorescence intensity of DNA QDs and the logarithmic values of arsenite concentration in the range of 1-150ppb with a detection limit of 0.2ppb (3σ) was obtained. The nanosensor shows excellent selectivity for "turn on" arsenite determination and arsenate does not show any interference, facilitating its application in complex real water analysis.
authors.affiliation: College of Chemistry and Institute for Advanced Study, Nanchang University, Nanchang, Jiangxi 330031, China.
authors.forename: Li
authors.initials: L
authors.lastname: Zhang
authors.affiliation: College of Chemistry and Institute for Advanced Study, Nanchang University, Nanchang, Jiangxi 330031, China.
authors.forename: Xiu-Zhi
authors.initials: XZ
authors.lastname: Cheng
authors.affiliation: College of Chemistry and Institute for Advanced Study, Nanchang University, Nanchang, Jiangxi 330031, China.
authors.forename: Lan
authors.initials: L
authors.lastname: Kuang
authors.affiliation: College of Chemistry and Institute for Advanced Study, Nanchang University, Nanchang, Jiangxi 330031, China.
authors.forename: Ai-Zhen
authors.initials: AZ
authors.lastname: Xu
authors.affiliation: College of Chemistry and Institute for Advanced Study, Nanchang University, Nanchang, Jiangxi 330031, China.
authors.forename: Ru-Ping
authors.initials: RP
authors.lastname: Liang
authors.affiliation: College of Chemistry and Institute for Advanced Study, Nanchang University, Nanchang, Jiangxi 330031, China; Department of Materials and Chemical Engineering, Pingxiang University, Pingxiang 337055, China. Electronic address: jdqiu@ncu.edu.cn.
authors.forename: Jian-Ding
authors.initials: JD
authors.lastname: Qiu
mesh_terms: D018053:Arsenites / Q000737:chemistry*; D015374:Biosensing Techniques / Q000379:methods*; D004277:DNA, Single-Stranded / Q000737:chemistry*; D005453:Fluorescence; D057230:Limit of Detection; D045663:Quantum Dots / Q000737:chemistry; D013050:Spectrometry, Fluorescence / Q000379:methods*
chemical_list: D018053:Arsenites; D004277:DNA, Single-Stranded
keywords: Arsenite; Assembly; DNA; Fluorescence enhancement; Quantum dots