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Journal of Nanomaterials
Volume 2017, Article ID 2160278, 9 pages
https://doi.org/10.1155/2017/2160278
Research Article

Luminomagnetic Silica-Coated Heterodimers of Core/Shell FePt/Fe3O4 and CdSe Quantum Dots as Potential Biomedical Sensor

1Departamento de Química, Universidade Federal de São Carlos (UFSCar), CP 676, 13565-905 São Carlos, SP, Brazil
2Instituto de Química de São Carlos, Universidade de São Paulo (USP), Colloidal Materials Group, CP 780, 13566-590 São Carlos, SP, Brazil
3Instituto Federal de Santa Catarina (IFSC), 89111-009 Gaspar, SC, Brazil

Correspondence should be addressed to Laudemir Carlos Varanda; rb.psu.csqi@adnaravl

Received 15 February 2017; Revised 1 May 2017; Accepted 14 May 2017; Published 11 June 2017

Academic Editor: Miguel A. Garcia

Copyright © 2017 Caio Guilherme Secco de Souza et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

We report the synthesis of a new multifunctional nanomaterial based on silica-coated FePt/Fe3O4-CdSe heteronanostructures, combining luminescent and magnetic properties in a promising bifunctional sensor for biomedical applications. Spherical Fe3O4-coated FePt (FePt/Fe3O4) superparamagnetic nanoparticles (10.8 ± 1.5 nm) with high saturation magnetization and controlled size and shape were obtained using thermal decomposition coupled with seed-mediated growth method. Luminescent property was added to the nanomaterial by using the FePt/Fe3O4 magnetic core as seed and growing the CdSe quantum dots (2.7 ± 0.6 nm) onto its surface in a heterodimer-like structure using the hot-injection approach. The FePt/Fe3O4-CdSe luminomagnetic heteronanostructures were coated with silica shell using the reverse-micelle microemulsion route to avoid solvent-quenching effects. After silica coating, the water-dispersible heteronanostructures showed a diameter of 25.3 ± 2 nm, high colloidal stability, magnetic saturation of around 11 emu g−1, and photoluminescence in the blue-green region, as expected for potential bifunctional platform in biomedical applications. The saturation magnetization of heteronanostructures can be increased to 28 emu g−1 by annealing at 550°C due to the presence of the FePt phase.