title: Proximity-dependent isothermal cycle amplification for small-molecule detection based on surface enhanced Raman scattering.
abstract: A novel proximity-dependent isothermal cycle amplification (PDICA) strategy has been proposed and successfully used for the determination of cocaine coupled with surface enhanced Raman scattering (SERS). For enhancing the SERS signal, Raman dye molecules modified bio-barcode DNA and gold nanoparticles (AuNPs) are used to prepare the Raman probes. Magnetic beads (MBs) are used as the carrier of amplification template and signal output products for circumventing the problem of high background induced by excess bio-barcode DNA. In the presence of target molecules, two label-free proximity probes can hybridize with each other and subsequently opens the hairpin connector-probe to perform the PDICA reaction including the target recycling amplification and strand-displacement amplification. As a result, abundant AuNPs Raman probes can be anchored on the surface of MBs and a low detection limit of 0.1 nM for cocaine is obtained. This assay also exhibits an excellent selectivity and has been successfully performed in human serum, which confirms the reliability and practicality of this protocol.
authors.affiliation: Key Laboratory of Biochemical Analysis, Ministry of Education, College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao 266042, PR China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Li
authors.forename: Yan
authors.initials: Y
authors.lastname: Zeng
authors.forename: Yaning
authors.initials: Y
authors.lastname: Mao
authors.forename: Chengcun
authors.initials: C
authors.lastname: Lei
authors.forename: Shusheng
authors.initials: S
authors.lastname: Zhang
mesh_terms: D052157:Aptamers, Nucleotide / Q000737:chemistry; D003042:Cocaine / Q000097:blood*; D006046:Gold / Q000737:chemistry*; D006801:Humans; D013287:Illicit Drugs / Q000097:blood*; D057230:Limit of Detection; D053758:Nanoparticles / Q000737:chemistry; D015203:Reproducibility of Results; D013059:Spectrum Analysis, Raman / Q000379:methods*; D015813:Substance Abuse Detection / Q000379:methods*
chemical_list: D052157:Aptamers, Nucleotide; D013287:Illicit Drugs; D006046:Gold; D003042:Cocaine
keywords: Aptamer; Cocaine; Dual recognition; Proximity-dependent isothermal cycle amplification; Surface-enhanced Raman scattering