Luminescence functionalization of mesoporous silica with different morphologies and applications as drug delivery systems

Ordered mesoporous silica (MCM-41) particles with different morphologies were synthesized through a simple hydrothermal process. Then these silica particles were functionalized with luminescent YVO4:EU3+ layers via the Pechini sol-gel process. The obtained YVO4:Eu3+ and MCM-41 composites, which maintained the mesoporous structure of MCM-41 and the red luminescence property of YVO4:Eu3+ were investigated as drug delivery systems using ibuprofen (IBU) as model drug. The physicochemical properties of the samples were characterized by X-ray diffraction (XRD), Fourier transform-infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), N-2 adsorption, and photoluminescence (PL) spectra, respectively. It is found that the specific surface area and pore volume, which are directly correlated with the drug-loading amount and drug release rate, decrease in sequence after the deposition Of YVO4:Eu3+ layer and the further incorporation of IBU. Additionally, the drug release test indicated that the IBU release rate could be controlled by regulating the morphology of the materials. It is worth noting that the I B U-incorporated samples still exhibit red luminescence under UV irradiation. Furthermore, the emission intensities of EU3+, can be tailored as a function of the released amount of IBU, thus making the drug release be easily tracked and monitored. (c) 2007 Elsevier Ltd. All rights reserved.