title: T-T mismatch-driven biosensor using triple functional DNA-protein conjugates for facile detection of Hg2+.
abstract: We report herein a T-T mismatch-driven biosensor using triple functional DNA-protein conjugates for facile detection of mercury ions (Hg(2+)) based on evanescent wave fluorescence excitation. Fluorescein-labeled DNA strands and streptavidin molecules were conjugated using heterobifunctional crosslinkers, and the obtained conjugates were named as "Hg(2+) dependent conjugates, HDCs". Initially hybridized with quencher-labeled DNA (Q-DNA) strands, HDCs showed low evanescent wave-induced fluorescence emission signals; however, in the presence of Hg(2+), the DNA moieties of HDCs tended to form hairpin structures stabilized by T-T mismatches, releasing Q-DNA strands, which was accompanied by increases in the fluorescent signals. The novel detection strategy enables the fluorescent detection of mercury ions with high specificity and a low detection limit of 1.06 nM in a facile way.
authors.affiliation: State Key Joint Laboratory of ESPC, Center for Sensor Technology of Environment and Health, School of environment, Tsinghua University, Beijing 100084, China.
authors.forename: Ruoyu
authors.initials: R
authors.lastname: Wang
authors.affiliation: State Key Joint Laboratory of ESPC, Center for Sensor Technology of Environment and Health, School of environment, Tsinghua University, Beijing 100084, China. Electronic address: xhzhou@mail.tsinghua.edu.cn.
authors.forename: Xiaohong
authors.initials: X
authors.lastname: Zhou
authors.affiliation: State Key Joint Laboratory of ESPC, Center for Sensor Technology of Environment and Health, School of environment, Tsinghua University, Beijing 100084, China.
authors.forename: Hanchang
authors.initials: H
authors.lastname: Shi
authors.affiliation: State Key Joint Laboratory of ESPC, Center for Sensor Technology of Environment and Health, School of environment, Tsinghua University, Beijing 100084, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Luo
mesh_terms: D020137:Base Pair Mismatch; D015374:Biosensing Techniques; D004247:DNA / Q000737:chemistry*; D005456:Fluorescent Dyes / Q000737:chemistry; D006046:Gold / Q000737:chemistry; D008628:Mercury / Q000302:isolation & purification*; D019809:Streptavidin / Q000737:chemistry; D014867:Water / Q000737:chemistry
chemical_list: D005456:Fluorescent Dyes; D014867:Water; D006046:Gold; D004247:DNA; D019809:Streptavidin; D008628:Mercury
keywords: DNA-protein conjugates; Evanescent wave; Mercury; Optical fiber biosensor; T–T mismatch