title: Hybrid magnetic nanoparticle/nanogold clusters and their distance-dependent metal-enhanced fluorescence effect via DNA hybridization.
abstract: To improve the metal-enhanced fluorescence (MEF) effect of nanogolds (AuNPs) and accurately detect specific DNA sequences via DNA hybridization, novel hybrid magnetic nanoparticles/nanogold clusters (HMNCs) were designed based on finite-difference time-domain simulation results and prepared by using Fe3O4 and nanogolds. The nanogolds outside the HMNC were then conjugated with thiol-terminated DNA molecules, thus DNA modified-HMNCs (DNA-HMNCs) were obtained. The size distributions of these nanostructures were measured by a Malvern size analyzer, and their morphology was observed via transmission electron microscopy (TEM). The ultraviolet (UV)-visible (vis) absorption spectra of the samples were recorded with a UV-2600 spectrophotometer. Fluorescence spectra and the MEF effect were recorded using a spectrophotofluorometer, and lifetimes were determined using a time-correlated single photon counting apparatus. The prepared HMNCs were stable in aqueous solutions and had an average diameter of 87 ± 3.2 nm, with six to eight AuNPs around a single Fe3O4 nanoparticle. Fluorescein isothiocyanate (FITC) tagged DNA-HMNC conjugates exhibited a significant MEF effect and could accurately detect specific DNA sequences after DNA hybridization. This result indicates their various potential applications in sensors and biomedical fields.
authors.affiliation: Key Laboratory of Biomedical Information Engineering of the Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, 710049, P. R. China. wudaocheng@mail.xjtu.edu.cn.
authors.forename: Xuefan
authors.initials: X
authors.lastname: Gu
authors.forename: Youshen
authors.initials: Y
authors.lastname: Wu
authors.forename: Lingze
authors.initials: L
authors.lastname: Zhang
authors.forename: Yongchun
authors.initials: Y
authors.lastname: Liu
authors.forename: Yan
authors.initials: Y
authors.lastname: Li
authors.forename: Yongli
authors.initials: Y
authors.lastname: Yan
authors.forename: Daocheng
authors.initials: D
authors.lastname: Wu
mesh_terms: D004247:DNA / Q000737:chemistry*; D004563:Electrochemistry; D016650:Fluorescein-5-isothiocyanate / Q000737:chemistry; D005453:Fluorescence; D006046:Gold / Q000737:chemistry*; D007501:Iron / Q000737:chemistry*; D060526:Magnetic Fields; D008280:Magnetics; D058185:Magnetite Nanoparticles / Q000737:chemistry*; D053768:Metal Nanoparticles / Q000737:chemistry*; D046529:Microscopy, Electron, Transmission; D036103:Nanotechnology; D009693:Nucleic Acid Hybridization; D010316:Particle Size; D017785:Photons; D012709:Serum Albumin / Q000737:chemistry; D012821:Silanes / Q000737:chemistry; D013050:Spectrometry, Fluorescence; D013056:Spectrophotometry, Ultraviolet; D013696:Temperature
chemical_list: D058185:Magnetite Nanoparticles; D012709:Serum Albumin; D012821:Silanes; D006046:Gold; D004247:DNA; D007501:Iron; D016650:Fluorescein-5-isothiocyanate