title: Aptamer-based label-free method for hemin recognition and DNA assay by capillary electrophoresis with chemiluminescence detection.
abstract: An aptamer-based label-free approach to hemin recognition and DNA assay using capillary electrophoresis with chemiluminescence detection is introduced here. Two guanine-rich DNA aptamers were used as the recognition element and target DNA, respectively. In the presence of potassium ions, the two aptamers folded into the G-quartet structures, binding hemin with high specificity and affinity. Based on the G-quartet-hemin interactions, the ligand molecule was specifically recognized with a Kd approximately 73 nM, and the target DNA could be detected at 0.1 microM. In phosphate buffer of pH 11.0, hemin catalyzed the H2O2-mediated oxidation of luminol to generate strong chemiluminescence signal; thus the target molecule itself served as an indicator for the molecule-aptamer interaction, which made the labeling and/or modification of aptamers or target molecules unnecessary. This label-free method for molecular recognition and DNA detection is therefore simple, easy, and effective.
authors.affiliation: State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin 130022, China.
authors.forename: Tao
authors.initials: T
authors.lastname: Li
authors.forename: Bingling
authors.initials: B
authors.lastname: Li
authors.forename: Shaojun
authors.initials: S
authors.lastname: Dong
mesh_terms: D052157:Aptamers, Nucleotide / Q000737:chemistry / Q000378:metabolism; D001665:Binding Sites; D015374:Biosensing Techniques / Q000379:methods*; D002384:Catalysis; D004247:DNA / Q000032:analysis* / Q000737:chemistry / Q000378:metabolism; D019075:Electrophoresis, Capillary / Q000379:methods*; D006147:Guanine / Q000031:analogs & derivatives / Q000378:metabolism; D006427:Hemin / Q000032:analysis* / Q000737:chemistry / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000737:chemistry; D008163:Luminescent Measurements / Q000379:methods*; D008165:Luminol / Q000737:chemistry; D010084:Oxidation-Reduction; D012680:Sensitivity and Specificity
chemical_list: D052157:Aptamers, Nucleotide; D008165:Luminol; D006147:Guanine; D006427:Hemin; D004247:DNA; D006861:Hydrogen Peroxide