title: Highly sensitive chemiluminescent detection of lead ion based on its displacement of potassium in G-Quadruplex DNAzyme.
abstract: A simple and highly sensitive method for detecting lead ion (Pb(2+)) in biosamples was developed based on its displacement of potassium in G-Quadruplex DNAzyme, which can catalyze the luminol-H2O2 chemiluminescence (CL) reaction. By introducing a G-rich DNA sequence, PS2.M, which can fold into a G-quadruplex when binding with hemin in the presence of K(+) and act as a superior horseradish peroxidase (HRP) mimicking-enzyme, we found this DNAzyme can effectively catalyze the H2O2-mediated oxidation of luminol, resulting in strong CL emission. The K(+)-stabilized G-quadruplex, upon the addition of Pb(2+), is transformed into a Pb(2+)-stabilized G-quadruplex with higher stability but poor DNAzyme activity, sharply decreasing the CL readout signal. With this, a simple and sensitive detection method for Pb(2+) in biosamples such as human hairs was developed with a linear range of 0.4-10 nM Pb(2+) and a limit of detection (3σ) of 0.06 nM. Owing to the introduction of G-quadruplex DNAzyme, which was employed not only as a sensing unit but also as a catalyst in the chemiluminescent assay, this method holds great potential for clinical plumbism diagnosis by testing hair.
authors.affiliation: Education Ministry Key Laboratory on Luminescence and Real-Time Analytical Chemistry, College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, China.
authors.forename: Hong
authors.initials: H
authors.lastname: Wang
authors.forename: Dong Mei
authors.initials: DM
authors.lastname: Wang
authors.forename: Cheng Zhi
authors.initials: CZ
authors.lastname: Huang
mesh_terms: D054856:G-Quadruplexes; D006197:Hair / Q000737:chemistry; D006801:Humans; D006861:Hydrogen Peroxide / Q000737:chemistry; D007477:Ions / Q000032:analysis; D007854:Lead / Q000032:analysis* / Q000737:chemistry; D057230:Limit of Detection; D008163:Luminescent Measurements / Q000379:methods*; D008165:Luminol / Q000737:chemistry; D011188:Potassium / Q000737:chemistry*
chemical_list: D007477:Ions; D007854:Lead; D008165:Luminol; D006861:Hydrogen Peroxide; D011188:Potassium