A magnetic, luminescent and mesoporous core-shell structured composite material as drug carrier

In this paper, hydrothermal synthesized Fe3O4 microspheres have been encapsulated with nonporous silica and a further layer of ordered mesoporous silica through a simple sol-gel process. The surface of the outer silica shell was further functionalized by the deposition of YVO4:Eu3+ phosphors, realizing a sandwich structured material with mesoporous, magnetic and luminescent properties. The multifunctional system was used as drug carrier to investigate the storage and release properties using ibuprofen (IBU) as model drug by the surface modification. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectra (XPS), Fourier transform infrared spectroscopy (FT-IR), N-2 adsorption/desorption, photoluminescence (PL) spectra, and superconducting quantum interference device (SQUID) were used to characterized the samples. The results reveal that the material shows typical ordered mesoporous characteristics, and have mono-disperse spherical morphology with smooth surface and narrow size distribution. Additionally, the multifunctional system shows the characteristic emission of Eu3+(D-5(0)-F-7(1-4)) even after the loading of drug molecules. Magnetism measurement reveals the superparamagnetic feature of the samples. Drug release test indicates that the multifunctional system shows drug sustained properties. Moreover, the emission intensities of Eu3+ in the drug carrier system increase with the released amount of drug, thus making the drug release be easily tracked and monitored by the change of the luminescence intensity. (C) 2009 Elsevier Ltd. All rights reserved.