title: Magnetically encoded luminescent composite nanoparticles through layer-by-layer self-assembly.
abstract: Sensitive and rapid detection of multiple analytes and the collection of components from complex samples are important in fields ranging from bioassays/chemical assays, clinical diagnosis, to environmental monitoring. A convenient strategy for creating magnetically encoded luminescent CdTe@SiO2 @n Fe3 O4 composite nanoparticles, by using a layer-by-layer self-assembly approach based on electrostatic interactions, is described. Silica-coated CdTe quantum dots (CdTe@SiO2 ) serve as core templates for the deposition of alternating layers of Fe3 O4 magnetic nanoparticles and poly(dimethyldiallyl ammonium chloride), to construct CdTe@SiO2 @n Fe3 O4 (n=1, 2, 3, …︁) composite nanoparticles with a defined number (n) of Fe3 O4 layers. Composite nanoparticles were characterized by zeta-potential analysis, fluorescence spectroscopy, vibrating sample magnetometry, and transmission electron microscopy, which showed that the CdTe@SiO2 @n Fe3 O4 composite nanoparticles exhibited excellent luminescence properties coupled with well-defined magnetic responses. To demonstrate the utility of these magnetically encoded nanoparticles for near-simultaneous detection and separation of multiple components from complex samples, three different fluorescently labeled IgG proteins, as model targets, were identified and collected from a mixture by using the CdTe@SiO2 @n Fe3 O4 nanoparticles.
authors.affiliation: Key Laboratory of Luminescence and Real-Time, Analytical Chemistry (Southwest University), Ministry of Education, College of Pharmaceutical Sciences, Southwest University, Chongqing, 400715 (P.R. China), Fax: (+86) 23-68251048. eqsong@swu.edu.cn.
authors.forename: Erqun
authors.initials: E
authors.lastname: Song
authors.forename: Weiye
authors.initials: W
authors.lastname: Han
authors.forename: Hongyan
authors.initials: H
authors.lastname: Xu
authors.forename: Yunfei
authors.initials: Y
authors.lastname: Jiang
authors.forename: Dan
authors.initials: D
authors.lastname: Cheng
authors.forename: Yang
authors.initials: Y
authors.lastname: Song
authors.forename: Mark T
authors.initials: MT
authors.lastname: Swihart
mesh_terms: D019187:Cadmium Compounds / Q000737:chemistry; D005290:Ferric Compounds / Q000737:chemistry; D049449:Luminescence; D008163:Luminescent Measurements / Q000379:methods; D008280:Magnetics / Q000379:methods*; D053761:Nanocomposites / Q000737:chemistry*; D045663:Quantum Dots; D012822:Silicon Dioxide / Q000737:chemistry; D013691:Tellurium / Q000737:chemistry
chemical_list: D019187:Cadmium Compounds; D005290:Ferric Compounds; C000499:ferric oxide; D012822:Silicon Dioxide; D013691:Tellurium; C028337:cadmium telluride
keywords: luminescence; magnetic properties; nanoparticles; quantum dots; self-assembly