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Synthesis of Core-shell Lanthanide-doped Upconversion Nanocrystals for Cellular Applications
Published on: November 10, 2017
In vivo bioimaging and sensitive detection of uranyl via a turn-on rare-earth functionalized covalent organic
Deshuai Zhen1, Yiru Wang1, Xinyu Zhang2
1Cancer Research Institute, The First Affiliated Hospital, School of Public Health, Hengyang Medical School, University of South China, Hengyang, 421001, PR China; State Key Laboratory of Chemo/Biosensing and Chemometrics, School of Chemistry and Chemical Engineering, Hunan University, Changsha, 410082, PR China.
Abstract:
Uranium, a radioactive and toxic pollutant, poses significant threats to human health. The development of sensitive platforms for uranium detection and bioimaging remains challenge. Herein, a pyridine-based covalent organic framework (COF) was synthesized via a Schiff-base reaction using 2,2'-bipyridine-5,5'-dicarbaldehyde (Bpydah) and 1,3,5-tris(4-aminophenyl)benzene (TAPB). Subsequently, europium ions (Eu3+) were anchored to the pyridinic nitrogen sites of the COF framework via post-synthetic coordination, enhancing the intrinsic fluorescence and yielding a europium-functionalized sensor (COF@Eu). Attributed to the combined contributions of photoinduced electron transfer (PET) and Förster resonance energy transfer (FRET), COF@Eu exhibits a fluorescence "turn-on" response toward uranyl ion (UO22+), with a detection limit of 3.3 nM and good reliability in complex sample matrices (RSD < 2.9%). Moreover, the "turn-on" fluorescence response, coupled with favorable biocompatibility and low cytotoxicity of COF@Eu, facilitates UO22+ imaging in cells and mice. This in vivo imaging capability highlights the potential of COF@Eu for visualizing internal uranium exposure. This work establishes a multifunctional platform, offering a potential strategy for environmental monitoring and nuclear toxicology.
