title: Dendrimers-based DNA biosensors for highly sensitive electrochemical detection of DNA hybridization using reporter probe DNA modified with Au nanoparticles.
abstract: A novel and sensitive electrochemical approach for sequence-specific DNA detection based on polyamidoamine (PAMAM) and signal amplification with nanoparticles (NPs) is reported. A gold electrode was first modified with 3-mercaptopropionic acid, and then reacted with an amino-terminated polyamidoamine (PAMAM, G 4.0-NH(2)) to obtain a thin film. Single-stranded 3'-biotin end-labeled oligonucleotide was immobilized onto the film to obtain a stable recognition layer through biotin-avidin combination to detect complementary target, using signal amplification with Au NPs and [Ru(NH(3))(6)](3+) as redox electroactive indicators. The properties of the avidin/PAMAM/3-mercaptopropionic acid (RSH)/Au, the characteristics of the immobilization and hybridization of DNA were studied by cyclic voltammetry (CV), difference pulse voltammetry (DPV) and electrochemical impedance spectroscopy. The dynamic detection range of the sequence-specific DNA was from 1.4 x 10(-11) to 2.7 x 10(-14) mol L(-1) and the detection limit was 1.4 x 10(-14) mol L(-1). The DNA sensor not only showed low detection limit, but also exhibited excellent selectivity against two-base mismatched DNA.
authors.affiliation: Key Laboratory of Eco-chemical Engineering, Ministry of Education, College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao 266042, China.
authors.forename: Guangjiu
authors.initials: G
authors.lastname: Li
authors.forename: Xiaolin
authors.initials: X
authors.lastname: Li
authors.forename: Jun
authors.initials: J
authors.lastname: Wan
authors.forename: Shusheng
authors.initials: S
authors.lastname: Zhang
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation*; D004247:DNA / Q000032:analysis* / Q000737:chemistry / Q000235:genetics; D015342:DNA Probes / Q000737:chemistry / Q000235:genetics; D004563:Electrochemistry / Q000295:instrumentation*; D004566:Electrodes; D004867:Equipment Design; D019544:Equipment Failure Analysis; D017930:Genes, Reporter; D006046:Gold / Q000737:chemistry*; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D009693:Nucleic Acid Hybridization / Q000379:methods*; D012680:Sensitivity and Specificity
chemical_list: D015342:DNA Probes; D006046:Gold; D004247:DNA