title: A redox active and electrochemiluminescent threading bis-intercalator and its applications in DNA assays.
abstract: A redox active and electrochemiluminescent (ECL) threading bis-intercalator, consisting of two N,N'-bis(3-propyl-imidazole)-1,4,5,8-naphthalene diimides (PIND) linked by a Ru(dmbpy)2(2+) (dmbpy = 4,4'-dimethyl-2,2'-bipyridine) complex (PIND-Ru-PIND), was synthesized for the first time. Its optical, electrochemical, and ECL properties were studied. UV-vis spectrophotometric measurements indicated that the two PIND groups bind to the double-stranded DNA (ds-DNA) in a threading intercalation mode, while the Ru(dmbpy)2(2+) reinforces the intercalation via electrostatic interaction with ds-DNA. An ECL DNA biosensor was fabricated using PIND-Ru-PIND. A 2000-fold sensitivity enhancement over direct voltammetry was obtained, making this an ultrasensitive system for ECL detection of DNA. Under optimized conditions, the biosensor allowed the detection of a target DNA in the range of 0.70-400 pM with a detection limit of 400 fM.
authors.affiliation: Institute of Bioengineering and Nanotechnology, 138669, Singapore.
authors.forename: Hong
authors.initials: H
authors.lastname: Xie
authors.forename: Natalia C
authors.initials: NC
authors.lastname: Tansil
authors.forename: Zhiqiang
authors.initials: Z
authors.lastname: Gao
mesh_terms: D015374:Biosensing Techniques; D004247:DNA / Q000737:chemistry*; D004563:Electrochemistry / Q000379:methods*; D004566:Electrodes; D006046:Gold / Q000737:chemistry; D007094:Imides / Q000737:chemistry; D007364:Intercalating Agents / Q000494:pharmacology*; D008163:Luminescent Measurements / Q000379:methods*; D008956:Models, Chemical; D009281:Naphthalenes / Q000737:chemistry; D010084:Oxidation-Reduction; D012428:Ruthenium / Q000737:chemistry*; D013053:Spectrophotometry; D013056:Spectrophotometry, Ultraviolet; D013997:Time Factors; D014466:Ultraviolet Rays
chemical_list: D007094:Imides; D007364:Intercalating Agents; D009281:Naphthalenes; C031721:naphthalene; D006046:Gold; D012428:Ruthenium; D004247:DNA