Synthesis and Characterization of Water-Soluble Conjugated Oligoelectrolytes for Near-Infrared Fluorescence Biological Imaging.
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.
Department of Cogno-Mechatronics Engineering, Pusan National University , Miryang 50463, Republic of Korea.
Shin-Jae
SJ
Woo
Department of Chemistry, Korea University , Seoul 02841, Republic of Korea.
Sungmin
S
Park
Department of Chemistry, Korea University , Seoul 02841, Republic of Korea.
Ji-Eun
JE
Jeong
Department of Radiology, College of Medicine, Yonsei University, YUHS-KRIBB Medical Convergence Research Institute , Seoul 03722, Republic of Korea.
Yoochan
Y
Hong
Department of Radiology, College of Medicine, Yonsei University, YUHS-KRIBB Medical Convergence Research Institute , Seoul 03722, Republic of Korea.|Brain Korea 21 PLUS Project for Medical Science, Yonsei University , Seoul 03722, Republic of Korea.
Minhee
M
Ku
Department of Physiology, School of Medicine, Pusan National University , Yangsan 50612, Republic of Korea.
Bo Yun
BY
Kim
Department of Physiology, School of Medicine, Pusan National University , Yangsan 50612, Republic of Korea.
Il Ho
IH
Jang
Department of Physiology, School of Medicine, Pusan National University , Yangsan 50612, Republic of Korea.
Soon Chul
SC
Heo
Division of Integrative Biosciences and Biotechnology, Department of Mechanical Engineering, Pohang University of Science and Technology , Pohang 37673, Republic of Korea.
Taejun
T
Wang
Division of Integrative Biosciences and Biotechnology, Department of Mechanical Engineering, Pohang University of Science and Technology , Pohang 37673, Republic of Korea.
Ki Hean
KH
Kim
Department of Radiology, College of Medicine, Yonsei University, YUHS-KRIBB Medical Convergence Research Institute , Seoul 03722, Republic of Korea.|Brain Korea 21 PLUS Project for Medical Science, Yonsei University , Seoul 03722, Republic of Korea.
Jaemoon
J
Yang
Department of Physiology, School of Medicine, Pusan National University , Yangsan 50612, Republic of Korea.
Jae Ho
JH
Kim
Department of Chemistry, Korea University , Seoul 02841, Republic of Korea.
Han Young
HY
Woo
D000818:Animals; D004573:Electrolytes / Q000138:chemical synthesis* / Q000737:chemistry; D005456:Fluorescent Dyes / Q000138:chemical synthesis* / Q000737:chemistry; D051379:Mice; D009369:Neoplasms / Q000000981:diagnostic imaging; D061848:Optical Imaging / Q000379:methods*; D014867:Water / Q000737:chemistry*
D004573:Electrolytes; D005456:Fluorescent Dyes; D014867:Water
Stokes shift; bioimaging; conjugated oligoelectrolytes; near-infrared fluorophores; vesicle