title: A fluorescence glucose sensor based on pH induced conformational switch of i-motif DNA.
abstract: A facile fluorescence biosensor for the detection of glucose is proposed based on the pH-induced conformational switch of i-motif DNA in this paper. Glucose can be oxidized by oxygen (O2) in the presence of glucose oxidase (GOD), and the generated gluconic acid can decrease the pH value of the solution and then induce the fluorophore- and quencher-labeled cytosine-rich single-stranded DNA to fold into a close-packed i-motif structure. As a result, the fluorescence quenching occurs because of the resonance energy transfer between fluorophore and quencher. Based on this working principle, the concentration of glucose can be detected by the decrease of fluorescence density. Under the optimal experimental conditions, the assay shows a linear response range of 5-100 µM for the glucose concentration with a detection limit of 4 µM. This glucose biosensor was applied to determine glucose in real samples successfully, suggesting its potential in the practical applicability.
authors.affiliation: State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, PR China; Department of Chemistry, University of Science and Technology of China (USTC), Hefei 230026, PR China.
authors.forename: Qingqing
authors.initials: Q
authors.lastname: Ke
authors.affiliation: State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, PR China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Zheng
authors.affiliation: State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, PR China.
authors.forename: Fan
authors.initials: F
authors.lastname: Yang
authors.affiliation: Department of Chemistry, University of Science and Technology of China (USTC), Hefei 230026, PR China. Electronic address: zhcww@ustc.edu.cn.
authors.forename: Hanchang
authors.initials: H
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, PR China. Electronic address: xryang@ciac.ac.cn.
authors.forename: Xiurong
authors.initials: X
authors.lastname: Yang
mesh_terms: D015374:Biosensing Techniques / Q000379:methods*; D001786:Blood Glucose / Q000737:chemistry*; D002942:Circular Dichroism; D004277:DNA, Single-Stranded / Q000737:chemistry*; D004305:Dose-Response Relationship, Drug; D005942:Gluconates / Q000737:chemistry; D005947:Glucose / Q000032:analysis*; D005949:Glucose Oxidase / Q000737:chemistry; D006029:Glycosuria / Q000652:urine*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D057230:Limit of Detection; D016014:Linear Models; D009690:Nucleic Acid Conformation; D013050:Spectrometry, Fluorescence / Q000379:methods*
chemical_list: D001786:Blood Glucose; D004277:DNA, Single-Stranded; D005942:Gluconates; D005949:Glucose Oxidase; D005947:Glucose; C030691:gluconic acid
keywords: Fluorescence; Glucose; I-motif DNA; pH