Core–Shell–Shell NaYbF4:Tm@CaF2@NaDyF4 Nanocomposites for Upconversion/T2-Weighted MRI/Computed Tomography Lymphatic Imaging

详细信息    查看全文

• 作者：Ying Li ; Yuyang Gu ; Wei Yuan ; Tianye Cao ; Kai Li ; Shiping Yang ; Zhiguo Zhou ; Fuyou Li
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2016
• 出版时间：August 3, 2016
• 年：2016
• 卷：8
• 期：30
• 页码：19208-19216
• 全文大小：439K
• 年卷期：0
• ISSN：1944-8252

文摘

To circumvent the defects of different bioimaging techniques, the development of multifunctional probes for multimodality bioimaging is required. In the present study, a lanthanide-based core–shell–shell nanocomposite NaYbF₄:Tm@CaF₂@NaDyF₄ composed of an ∼9.5 nm NaYbF₄:Tm nanocrystal as the core, ∼2 nm CaF₂ as the middle layer, and 1–2 nm NaDyF₄ as the outermost shell was designed and synthesized. Following surface modification with the ligand, citrate acid, this nanocomposite was hydrophilic, emitted intense upconversion luminescence (UCL), and displayed a high X-ray computed tomography (CT) value of ∼490 Hounsfield units (HU) and excellent r₂ relaxivity of 41.1 mM^–1 s^–1. These results confirmed that the introduction of a middle CaF₂ layer was necessary as a barrier to reduce cross-relaxation and the surface quenching effect, thus enhancing the upconversion emission of Tm³⁺. This citrate-modified NaYbF₄:Tm@CaF₂@NaDyF₄ nanocomposite was used as a multifunctional contrast agent for trimodal lymphatic bioimaging with T₂-weighted magnetic resonance imaging (MRI), CT, and UCL imaging. The concept of fabricating a core–multishell nanostructure and the introduction of a Dy³⁺-based host as an outer layer is a useful strategy and can be used to develop a novel multifunctional nanoprobe for multimodality bioimaging.