title: A new electrochemical biosensor for DNA detection based on molecular recognition and lead sulfide nanoparticles.
abstract: In this paper, we constructed a new electrochemical biosensor for DNA detection based on a molecule recognition technique. In this sensing protocol, a novel dual-labeled DNA probe (DLP) in a stem-loop structure was employed, which was designed with dabcyl labeled at the 3' end as a guest molecule, and with a Pb nanoparticle labeled at the 5' end as electrochemical tag to indicate hybridization. One α-cyclodextrin-modified electrode (α-CD/MCNT/GCE) was used for capturing the DNA hybridization. Initially, the DLP was in the "closed" state in the absence of the target, which shielded dabcyl from the bulky α-CD/MCNT/GCE conjugate due to a steric effect. After hybridization, the loop sequence (16 bases) formed a rigid duplex with the target, breaking the relatively shorter stem duplex (6 bases). Consequently, dabcyl was forced away from the Pb nanoparticle and became accessible by the electrode. Therefore, the target hybridization event can be sensitively transduced via detecting the electrochemical reduction current signal of Pb. Using this method, as low as 7.1×10(-10)M DNA target had been detected with excellent differentiation ability for even a single mismatch.
authors.affiliation: Department of Pharmacy, JiangXi University of Traditional Chinese Medicine, JiangXi 330004, China. fanhao11@yahoo.com.cn
authors.forename: Hao
authors.initials: H
authors.lastname: Fan
authors.forename: Kun
authors.initials: K
authors.lastname: Zhao
authors.forename: Yan
authors.initials: Y
authors.lastname: Lin
authors.forename: Xiaoyun
authors.initials: X
authors.lastname: Wang
authors.forename: Bo
authors.initials: B
authors.lastname: Wu
authors.forename: Qianggen
authors.initials: Q
authors.lastname: Li
authors.forename: Lin
authors.initials: L
authors.lastname: Cheng
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation*; D002244:Carbon / Q000737:chemistry; D004247:DNA / Q000032:analysis* / Q000235:genetics*; D015342:DNA Probes / Q000378:metabolism; D055664:Electrochemical Techniques / Q000295:instrumentation* / Q000379:methods*; D004566:Electrodes; D005898:Glass / Q000737:chemistry; D007854:Lead / Q000737:chemistry*; D008968:Molecular Conformation; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D037742:Nanotubes, Carbon / Q000648:ultrastructure; D009693:Nucleic Acid Hybridization; D013056:Spectrophotometry, Ultraviolet; D017550:Spectroscopy, Fourier Transform Infrared; D013440:Sulfides / Q000737:chemistry*; D013997:Time Factors; D047391:alpha-Cyclodextrins / Q000737:chemistry; D004124:p-Dimethylaminoazobenzene / Q000031:analogs & derivatives / Q000737:chemistry
chemical_list: D015342:DNA Probes; D037742:Nanotubes, Carbon; D013440:Sulfides; D047391:alpha-Cyclodextrins; C018391:lead sulfide; D007854:Lead; C063127:4-(4-dimethylaminophenylazo)benzoic acid; D002244:Carbon; D004247:DNA; D004124:p-Dimethylaminoazobenzene; C032613:alpha-cyclodextrin