title: Plasmon coupling-enhanced two-photon photoluminescence of Au@Ag core-shell nanoparticles and applications in the nuclease assay.
abstract: Au and Ag nanoparticles (NPs) have been known to display significantly enhanced two-photon photoluminescence (2PPL) upon the formation of nanoparticle aggregates. The enhancement effect of the core-shell nanoparticles has not been explored so far. Here we have prepared Au@Ag bimetallic core-shell nanoparticles with different thicknesses (1.1, 2.1, 3.5, 4.5, and 5.5 nm) of silver coating on 19 nm Au NPs to investigate the composition effects on plasmon coupling-enhanced 2PPL. A maximum 2PPL enhancement factor (IcoupledNPs/IisolatedNPs) of up to 840-fold was obtained for Au@Ag NPs with ∼3.5 nm Ag nanoshells. These Au@Ag NPs were subsequently utilized in two-photon detection of S1 nuclease as a photoluminescence turn on probe. This method displayed high sensitivity with the limit of detection of 1.4 × 10(-6) U μL(-1) and an excellent selectivity.
authors.affiliation: Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543. chmxqh@nus.edu.sg.
authors.forename: Peiyan
authors.initials: P
authors.lastname: Yuan
authors.forename: Rizhao
authors.initials: R
authors.lastname: Ma
authors.forename: Nengyue
authors.initials: N
authors.lastname: Gao
authors.forename: Monalisa
authors.initials: M
authors.lastname: Garai
authors.forename: Qing-Hua
authors.initials: QH
authors.lastname: Xu
mesh_terms: D004706:Endodeoxyribonucleases / Q000378:metabolism; D006046:Gold / Q000737:chemistry*; D057230:Limit of Detection; D053768:Metal Nanoparticles / Q000737:chemistry*; D012834:Silver / Q000737:chemistry*
chemical_list: D012834:Silver; D006046:Gold; D004706:Endodeoxyribonucleases