title: Optimization of strand displacement amplification-sensitized G-quadruplex DNAzyme-based sensing system and its application in activity detection of uracil-DNA glycosylase.
abstract: As an isothermal nucleic acid amplification technique, strand displacement amplification (SDA) reaction has been introduced in G-quadruplex DNAzyme-based sensing system to improve the sensing performance. To further provide useful information for the design of SDA-amplified G-quadruplex DNAzyme-based sensors, the effects of nicking site number in SDA template DNA were investigated. With the increase of the nicking site number from 1 to 2, enrichment of G-quadruplex DNAzyme by SDA is changed from a linear amplification to an exponential amplification, thus greatly increasing the amplification efficiency and subsequently improving the sensing performance of corresponding sensing system. The nicking site number cannot be further increased because more nicking sites might result in high background signals. However, we demonstrated that G-quadruplex DNAzyme enrichment efficiency could be further improved by introducing a cross-triggered SDA strategy, in which two templates each has two nicking sites are used. To validate the proposed cross-triggered SDA strategy, we used it to develop a sensing platform for the detection of uracil-DNA glycosylase (UDG) activity. The sensor enables sensitive detection of UDG activity in the range of 1 × 10(-4)-1 U/mL with a detection limit of 1 × 10(-4)U/mL.
authors.affiliation: State Key Laboratory of Medicinal Chemical Biology, Research Centre for Analytical Sciences, Nankai University, Tianjin 300071, PR China; Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin 300071, PR China.
authors.forename: Yi-Chen
authors.initials: YC
authors.lastname: Du
authors.affiliation: State Key Laboratory of Medicinal Chemical Biology, Research Centre for Analytical Sciences, Nankai University, Tianjin 300071, PR China; Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin 300071, PR China.
authors.forename: Hong-Xin
authors.initials: HX
authors.lastname: Jiang
authors.affiliation: State Key Laboratory of Medicinal Chemical Biology, Research Centre for Analytical Sciences, Nankai University, Tianjin 300071, PR China; Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin 300071, PR China.
authors.forename: Yan-Fang
authors.initials: YF
authors.lastname: Huo
authors.affiliation: State Key Laboratory of Medicinal Chemical Biology, Research Centre for Analytical Sciences, Nankai University, Tianjin 300071, PR China; Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin 300071, PR China.
authors.forename: Gui-Mei
authors.initials: GM
authors.lastname: Han
authors.affiliation: State Key Laboratory of Medicinal Chemical Biology, Research Centre for Analytical Sciences, Nankai University, Tianjin 300071, PR China; Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin 300071, PR China.
authors.forename: De-Ming
authors.initials: DM
authors.lastname: Kong
mesh_terms: D053904:DNA Breaks, Single-Stranded; D021881:DNA, Catalytic / Q000737:chemistry* / Q000235:genetics; D004789:Enzyme Activation; D004867:Equipment Design; D019544:Equipment Failure Analysis; D054856:G-Quadruplexes; D021141:Nucleic Acid Amplification Techniques / Q000295:instrumentation*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013056:Spectrophotometry, Ultraviolet / Q000295:instrumentation*; D051981:Uracil-DNA Glycosidase / Q000032:analysis* / Q000737:chemistry*
chemical_list: D021881:DNA, Catalytic; D051981:Uracil-DNA Glycosidase
keywords: DNAzyme; G-quadruplex; Sensor; Strand displacement amplification (SDA); Uracil-DNA glycosylase (UDG)