Synthesis and Characterization of Water-Soluble Conjugated Oligoelectrolytes for Near-Infrared Fluorescence Biological Imaging

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• 作者：Shin-Jae Woo ; Sungmin Park ; Ji-Eun Jeong ; Yoochan Hong ; Minhee Ku ; Bo Yun Kim ; Il Ho Jang ; Soon Chul Heo ; Taejun Wang ; Ki Hean Kim ; Jaemoon Yang ; Jae Ho Kim ; Han Young Woo
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2016
• 出版时间：June 29, 2016
• 年：2016
• 卷：8
• 期：25
• 页码：15937-15947
• 全文大小：640K
• 年卷期：0
• ISSN：1944-8252

文摘

Near-infrared (NIR) fluorophores attract increasing attention as a molecular marker (or probe) for in vivo and in vitro biological fluorescence imaging. Three types of new NIR fluorescent conjugated oligoelectrolytes (COEs: Q-FlTBTTFl, Q-FlBBTFl, and Q-FlTBBTTFl) are synthesized with quaternized ammonium ionic groups in their side-chains for water solubility. The emission wavelength is modulated in the range 600–1300 nm, by adjusting the intramolecular charge transfer in the molecular backbone based on the electron-rich fluorene (and/or thiophene) and electron-deficient benzo[2,1,3]thiadiazole (or benzo[1,2-c:4,5-c′]bis[1,2,5]thiadiazole) moieties. The COEs show a remarkably larger Stokes shift (147–276 nm) compared to commercial rhodamine and cyanine dyes in water, avoiding self-quenching and interference from the excitation backscattered light. The photoluminescence (PL) quantum efficiency is improved substantially by up to 27.8% in water by fabricating a vesicular complex, COE/v, with a block ionomer, poly[(ethylene oxide)-block-(sodium 2-acrylamido-2-methyl-1-propanesulfonate)]. In vitro cellular uptake images with the COEs are obtained with good biocompatibility by confocal single-photon and two-photon microscopy. The ex vivo and in vivo images of a mouse xenograft model treated with the Q-FlBBTFl/v exhibit a substantially stronger fluorescence signal at the tumor site than at the other organs, highlighting the potential of the COE/v as an NIR fluorescent imaging agent for the diagnosis of cancer.