title: DNAzyme-based plasmonic nanomachine for ultrasensitive selective surface-enhanced Raman scattering detection of lead ions via a particle-on-a-film hot spot construction.
abstract: We propose a highly sensitive and selective surface-enhanced Raman scattering (SERS) method for determining lead ions based on a DNAzyme-linked plasmonic nanomachine. A metallic nanoparticle-on-a-film structure was built through a rigid double-stranded bridge linker composed of a DNAzyme and its substrate. This DNAzyme could be activated by lead ions and catalyze a fracture action of the substrate. Thus, the double chain structure of DNA would turn into a flexible single strand, making the metal nanoparticles that connected to the terminal of DNAzyme fall to the surface of the metal film. Hereby, a narrow gap close to 2 nm generated between metal nanoparticles and the metal film, exhibiting a similar effect of a "hot spot" and remarkably enhancing the signal of randomly dispersed Raman-active molecules on the surface of metal film. By measuring the improvement of SERS intensity of the Raman-active molecules, we realized the lowest detection concentration of Pb(2+) ions to 1.0 nM. This SERS analytical method is highly selective and can be extended universally to other targets via the accurate programming of corresponding DNA sequences.
authors.affiliation: State Key Laboratory of Supramolecular Structure and Materials, Institute of Theoretical Chemistry, Jilin University , 2699 Qianjin Avenue, Changchun 130012, P. R. China.
authors.forename: Cuicui
authors.initials: C
authors.lastname: Fu
authors.forename: Weiqing
authors.initials: W
authors.lastname: Xu
authors.forename: Hailong
authors.initials: H
authors.lastname: Wang
authors.forename: Han
authors.initials: H
authors.lastname: Ding
authors.forename: Lijia
authors.initials: L
authors.lastname: Liang
authors.forename: Ming
authors.initials: M
authors.lastname: Cong
authors.forename: Shuping
authors.initials: S
authors.lastname: Xu
mesh_terms: D021881:DNA, Catalytic / Q000378:metabolism*; D007477:Ions / Q000032:analysis / Q000378:metabolism; D007854:Lead / Q000032:analysis* / Q000378:metabolism; D053768:Metal Nanoparticles / Q000737:chemistry; D036103:Nanotechnology; D010316:Particle Size; D013059:Spectrum Analysis, Raman; D013499:Surface Properties
chemical_list: D021881:DNA, Catalytic; D007477:Ions; D007854:Lead