Europium-Doped TiO2 Hollow Nanoshells: Two-Photon Imaging of Cell Binding

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• 作者：Sergio Sandoval ; Jian Yang ; Jesus G. Alfaro ; Alexander Liberman ; Milan Makale ; Casey E. Chiang ; Ivan K. Schuller ; Andrew C. Kummel ; William C. Trogler
• 刊名：Chemistry of Materials
• 出版年：2012
• 出版时间：November 13, 2012
• 年：2012
• 卷：24
• 期：21
• 页码：4222-4230
• 全文大小：605K
• 年卷期：v.24,no.21(November 13, 2012)
• ISSN：1520-5002

文摘

A simple scalable method to fabricate luminescent monodisperse 200 nm europium-doped hollow TiO₂ nanoshell (NS) particles is reported. Fluorophore reporter, Eu³⁺ ions are incorporated directly in the NS matrix, leaving the surface free for functionalization and the core free for payload encapsulation. Amine-functionalized polystyrene beads were used as templates, and the porous walls of europium-doped titania nanoshells were synthesized using titanium(IV) t-butoxide and europium(III) nitrate as reactants. X-ray diffraction analysis identified anatase as the predominant titania phase of the rigid nanoshell wall structure, and photoluminescence spectra showed that the Eu(III)-doped TiO₂ nanoshells exhibited a red emission at 617 nm due to an atomic f鈥揻 transition. Nanoshell interactions with HeLa cervical cancer cells in vitro were visualized using two-photon microscopy of the Eu(III) emission and studied using a luminescence ratio analysis to assess nanoshell adhesion and endocytosis.

Keywords:

two photon; microscopy; titania; nanoshells; europium(III); luminescence; anatase; HeLa; polyethyleneimine; SEM; TEM; DLS