title: Electrochemiluminescent lead biosensor based on GR-5 lead-dependent DNAzyme for Ru(phen)3(2+) intercalation and lead recognition.
abstract: An electrochemiluminescent (ECL) lead biosensor was developed based on GR-5 lead-dependent DNAzyme for lead recognition and intercalated ruthenium tris(1,10-phenanthroline) (Ru(phen)(3)(2+)) as the ECL probe. The thiol-modified substrate was first immobilized on the surface of the gold electrode via gold-sulfur self-assembly. Subsequently, the hybridization of DNAzyme and its substrate and the automatic intercalation of Ru(phen)(3)(2+) proceeded. Intercalated Ru(phen)(3)(2+) can transfer electrons through double-stranded DNA to the electrode and its electrochemiluminescence was excited with a potential step using tripropylamine as the coreactant. In the presence of lead, the substrate cleaves at the scissile ribo-adenine into two fragments. The dissociation of DNAzyme occurs, leading to the releasing of intercalated Ru(phen)(3)(2+) accompanied by a decrease in the intensity of electrochemiluminescence. A quantity of lead can be calculated from this decrease. The biosensor is highly sensitive and specific, along with an ultra-low limit of detection of 0.9 pM and a dynamic range from 2 to 1000 pM. It enables analysis of trace amounts of lead in serum samples. The combination of the intercalated-Ru(phen)(3)(2+) ECL probe and the cofactor-dependent DNAzyme may push the performance of cofactor-sensing tactics to the extreme.
authors.affiliation: State Key Laboratory of Medicinal Chemical Biology, College of Chemistry, Nankai University, Tianjin, 300071, P.R. China.
authors.forename: Ai
authors.initials: A
authors.lastname: Gao
authors.forename: Chun-Xia
authors.initials: CX
authors.lastname: Tang
authors.forename: Xi-Wen
authors.initials: XW
authors.lastname: He
authors.forename: Xue-Bo
authors.initials: XB
authors.lastname: Yin
mesh_terms: D001483:Base Sequence; D015374:Biosensing Techniques / Q000379:methods*; D021881:DNA, Catalytic / Q000235:genetics / Q000378:metabolism*; D004563:Electrochemistry; D007854:Lead / Q000737:chemistry / Q000378:metabolism*; D057230:Limit of Detection; D008163:Luminescent Measurements; D009942:Organometallic Compounds / Q000737:chemistry*; D010084:Oxidation-Reduction; D010618:Phenanthrolines / Q000737:chemistry*; D011437:Propylamines / Q000737:chemistry
chemical_list: D021881:DNA, Catalytic; D009942:Organometallic Compounds; D010618:Phenanthrolines; D011437:Propylamines; C096226:tripropylamine; C034282:tris-(1,10-phenanthroline)ruthenium; D007854:Lead