title: Cocaine detection via rolling circle amplification of short DNA strand separated by magnetic beads.
abstract: A novel and sensitive fluorescence biosensor based on aptamer and rolling circle amplification for the determination of cocaine was developed in the present work. Here cocaine aptamers immobilized onto Au nanoparticles modified magnetic beads hybridized with short DNA strand. In the presence of cocaine, the short DNA strand was displaced from aptamer owing to cocaine specially binding with aptamer. Next, the short DNA strand was separated by magnetic beads and used to originate rolling circle amplification as primer. The end products of rolling circle amplification were detected by fluorescence signal generation upon molecular beacons hybridizing with the end products of rolling circle amplification. With rolling circle amplification and the separation by magnetic beads reducing the background signal, the new strategy was suitable for the detection of as low as 0.48 nM cocaine. Compared with reported cocaine sensors, our method exhibited excellent sensitivity. Our new strategy may provide a platform for numerous proteins and low molecular weight analytes to highly sensitively detect by DNA amplification.
authors.affiliation: State Key Laboratory Base of Eco-chemical Engineering, College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao, PR China.
authors.forename: Cuiping
authors.initials: C
authors.lastname: Ma
authors.forename: Wenshuo
authors.initials: W
authors.lastname: Wang
authors.forename: Qing
authors.initials: Q
authors.lastname: Yang
authors.forename: Chao
authors.initials: C
authors.lastname: Shi
authors.forename: Lijie
authors.initials: L
authors.lastname: Cao
mesh_terms: D052157:Aptamers, Nucleotide / Q000737:chemistry*; D015374:Biosensing Techniques / Q000379:methods*; D003042:Cocaine / Q000032:analysis*; D004247:DNA / Q000737:chemistry*; D006046:Gold / Q000737:chemistry*; D008280:Magnetics; D053758:Nanoparticles / Q000737:chemistry*; D012680:Sensitivity and Specificity
chemical_list: D052157:Aptamers, Nucleotide; D006046:Gold; D004247:DNA; D003042:Cocaine