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

Author(s)

Secco de Souza, Caio Guilherme ; Souza, Joao Batista, Jr. ; Beck, Watson, Jr. ; Varanda, Laudemir Carlos

• Document type: Journal article
• Source: Journal of Nanomaterials; v. 2017, p. 9-pg., 2017-01-01.

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 degrees C due to the presence of the FePt phase. (AU)

• FAPESP's process: 13/01284-2 - Theranostic nanoparticles based in superparamagnetic iron oxide for skin cancer therapy by magnetic hyperthermia
• Grantee: Laudemir Carlos Varanda
• Support Opportunities: Regular Research Grants
• FAPESP's process: 12/02093-3 - Synthesis of Co@Au (superparamagnetics) and CdSe@Zn (quantum dots) core@shell nanostructures for applications as antineoplasia agents
• Grantee: João Batista Souza Junior
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 07/07919-9 - Colloidal magnetic nanocrystals: synthesis of self-assembled and macromolecules-functionalised nanospheres, nanowires, and nanorods for advanced magnetic recording, biotechnological, and biomedical applications
• Grantee: Laudemir Carlos Varanda
• Support Opportunities: Research Grants - Young Investigators Grants