Gd2O3:Eu3+@mesoporous SiO2 bifunctional core–shell composites: Fluorescence label and drug release

A novel kind of core–shell nanocomposite Gd2O3:Eu3+@mesoporous SiO2 was successfully fabricated, which consisted of a solvothermal synthesized Gd2O3:Eu3+ nanospheres core, a thin nonporous silica midterm layer and an ordered mesoporous silica shell. The XRD, SEM, TEM, FTIR, N2 adsorption/desorption and PL spectra were employed to characterize the composites. The cytotoxicity of Gd2O3:Eu3+@mesoporous SiO2 and Gd2O3:Eu3+ was assessed by the standard MTT assay. The composites had spherically monodisperse morphology and a narrow size distribution around 180 nm in diameter. Furthermore, they also demonstrated the strong photoluminescence of 5D0–7FJ emissions. In addition, the composites exhibited good property of sustained drug release by using ibuprofen (IBU) as model drug in the drug delivery process. Therefore, the drug release process could be easily tracked and identified through photoluminescence. Overall, the present composites have potential significant biomedical application as ideal bifunctional materials.

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► We fabricated a novel kind of core–shell nanocomposite Gd2O3:Eu3+@nSiO2@mSiO2 by solvothermal and modified stöber methods.
► The composite displays bright PL, and contains ordered mesoporous with relatively large drug loading capacity (12.1 wt.%).
► The release experiments reveal that this drug storage system exhibits the sustained-release property.
► The composite shows little cytotoxicity (below 10 μg/mL) or slight cytotoxicity (range of 20–200 μg/mL) according to the MTT assay.