title: A single-bead telomere sensor based on fluorescence resonance energy transfer.
abstract: We present a 200 nm in-diameter single-bead sensor for the detection of single, unlabeled DNA molecules in solution using fluorescence resonance energy transfer technology. DNA-bound Alexa 488 and Crimson 625 loaded on commercial beads served as the donor and acceptor, respectively. Binding of the target DNA to the single bead sensor induces G-quadruplex stretching, resulting in a decrease in fluorescence energy transfer. G-rich telomere sequences formed a G-quadruplex structure in the presence of ZnTCPP, as demonstrated by the detection of two strong donor and acceptor signals. The sensitivity of the sensor was 1 fM. Under optimized conditions using a polydimethylsiloxane microfluidic device, we measured the number of sensor beads by direct counting. By controlling the flow rate via the probe volume, one sensing experiment can be completed in 5 minutes. Based on these results, we propose a new parameter-dependability (RS)-as a quantitative measure to judge the quality of a bio-sensor. This parameter is based on the ratio of the sensor and sensing sample fluorescence signals. This parameter can range from 0.1 to 100, where a value of 10 represents an optimized bio-sensor.
authors.affiliation: School of Chemistry and Chemical Engineering, Jiangsu Normal University, Xuzhou 221116, China. lh0002@gmail.com.
authors.forename: Xiao
authors.initials: X
authors.lastname: Fan
authors.affiliation: Department of Chemistry, Liaocheng University, Liaocheng 252059, China.
authors.forename: Qiaoli
authors.initials: Q
authors.lastname: Yue
authors.affiliation: School of Chemistry and Chemical Engineering, Jiangsu Normal University, Xuzhou 221116, China. lh0002@gmail.com.
authors.forename: Yanyan
authors.initials: Y
authors.lastname: Li
authors.affiliation: School of Chemistry and Chemical Engineering, Jiangsu Normal University, Xuzhou 221116, China. lh0002@gmail.com.
authors.forename: Yingya
authors.initials: Y
authors.lastname: Liu
authors.affiliation: School of Chemistry and Chemical Engineering, Jiangsu Normal University, Xuzhou 221116, China. lh0002@gmail.com.
authors.forename: Lu-Lu
authors.initials: LL
authors.lastname: Qu
authors.affiliation: School of Chemistry and Chemical Engineering, Jiangsu Normal University, Xuzhou 221116, China. lh0002@gmail.com.
authors.forename: Yingnan
authors.initials: Y
authors.lastname: Cao
authors.affiliation: School of Chemistry and Chemical Engineering, Jiangsu Normal University, Xuzhou 221116, China. lh0002@gmail.com and Department of Chemistry, Cambridge University, Cambridge CB2 1EW, UK.
authors.forename: Haitao
authors.initials: H
authors.lastname: Li
mesh_terms: D015374:Biosensing Techniques; D004247:DNA; D005453:Fluorescence; D031541:Fluorescence Resonance Energy Transfer; D054856:G-Quadruplexes; D016615:Telomere / Q000737:chemistry*
chemical_list: D004247:DNA