title: Metal-organic framework MIL-101 as a low background signal platform for label-free DNA detection.
abstract: A label-free and sensitive fluorescence method for recognition of sequence-specific DNA using DNA-intercalating dye and metal-organic frameworks (MOFs) is developed. Here, MIL-101 (Cr3F(H2O)2O[(O2C)-C6H4-(CO2)]3·nH2O) is introduced as a quenching platform to decrease the high background fluorescence of SYBR Green I (SG)/probe DNA complex. Mechanism investigations show that MIL-101 can strongly adsorb the SG/probe DNA complex through π-π stacking and electrostatic interactions, and as a consequence, the fluorescence of the SG dye is greatly quenched. While in the presence of target DNA, the as-formed rigid double-stranded (ds) structure of DNA will be far away from the surface of MIL-101; meanwhile, the SG dye can be bound with the dsDNA in the mode of intercalation and minor groove binding, resulting in enhancement of the SG dye fluorescence. The increased signal-to-background ratio has a linear relationship with the concentration of target DNA in the range of 0.1-14 nM. It is confirmed that the detection limit is 73 pM (3σ), which is much lower than that based on the carbon nanotubes and graphene oxide platform. Moreover, one-base-mismatched target DNA can be discriminated effectively. With the introduction of MIL-101, the signal-to-background ratio has been improved ∼8-fold, demonstrating that MIL-101 is an efficient low-background signal platform.
authors.affiliation: Education Ministry Key Laboratory on Luminescence and Real-Time Analysis, College of Chemistry and Chemical Engineering Southwest University, Chongqing 400715, China. liyf@swu.edu.cn.
authors.forename: Jing Mei
authors.initials: JM
authors.lastname: Fang
authors.forename: Fei
authors.initials: F
authors.lastname: Leng
authors.forename: Xi Juan
authors.initials: XJ
authors.lastname: Zhao
authors.forename: Xiao Li
authors.initials: XL
authors.lastname: Hu
authors.forename: Yuan Fang
authors.initials: YF
authors.lastname: Li
mesh_terms: D001483:Base Sequence; D015374:Biosensing Techniques / Q000379:methods; D056831:Coordination Complexes / Q000737:chemistry*; D004279:DNA, Viral / Q000032:analysis* / Q000737:chemistry; D015497:HIV-1 / Q000235:genetics*; D057230:Limit of Detection; D000073396:Metal-Organic Frameworks; D009942:Organometallic Compounds / Q000737:chemistry*; D013050:Spectrometry, Fluorescence / Q000379:methods*; D055672:Static Electricity
chemical_list: D056831:Coordination Complexes; D004279:DNA, Viral; C000589635:MIL-101; D000073396:Metal-Organic Frameworks; D009942:Organometallic Compounds