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.

Study of Molecular Conformation and Activity-Related Properties of Lipase Immobilized onto Core–Shell Structured Polyacrylic Acid-Coated Magnetic Silica Nanocomposite Particles

“…4,5 This problem can be avoided by coating of these magnetic nanoparticles with silica (i.e., core−shell morphology), which provides high stability under various reaction environments, good water solubility, excellent biocompatibility, and enriched chemistry for further surface modification. 6,7 Magnetic silica nanocomposite particles have been prepared and studied for a large number of bio/medical applications including bioseparation, 8 catalysis, 9 magnetic resonance imaging, 10 biomedicine, 11 separation of environmental contaminants, 12 and enzyme immobilization. 13 Enzymes are widely used as versatile biocatalysts in a broad range of reactions.…”

“…Iron oxide nanoparticles are promising candidate for a broad range of applications, because of their high specific surface area, easy and low-cost synthesis, low cytotoxicity, and great magnetic responsiveness. − However, their chemical stability is low under severe acidic and oxidative reaction conditions. , This problem can be avoided by coating of these magnetic nanoparticles with silica (i.e., core–shell morphology), which provides high stability under various reaction environments, good water solubility, excellent biocompatibility, and enriched chemistry for further surface modification. , Magnetic silica nanocomposite particles have been prepared and studied for a large number of bio/medical applications including bioseparation, catalysis, magnetic resonance imaging, biomedicine, separation of environmental contaminants, and enzyme immobilization …”

Stepwise assembly of a cross-linked free-standing nanoparticle sheet with controllable shape

“…7c and d are captured in a direction parallel and perpendicular to the applied magnetic field, respectively. Moreover, since the fluorescent magnetic nanoparticle ensemble has been widely utilized in the literature for the separation and detection of biomolecules, 46,47 the application of current Fe 3 O 4 -PEG-CdSe in such fields is also greatly anticipated.…”

Sandwich Immunoassays of Multicomponent Subtrace Pathogenic DNA Based on Magnetic Fluorescent Encoded Nanoparticles

“…Magnetic fluorescent encoded nanoparticles are a kind of novel multifunctional nanoparticle with magnetic and fluorescent encoding properties, being the attractive nanomaterial in multivariate analysis and separation technology due to its excellent characteristics, such as the integration of the advantages of magnetism and fluorescent encoding, multicomponent labeling, and targeted separation [ 17 – 20 ]. Recently, the design, synthesis, functionalization, and application of magnetic fluorescent encoded nanoparticles have attracted much attention.…”