title: Dual-modal MRI contrast agent with aggregation-induced emission characteristic for liver specific imaging with long circulation lifetime.
abstract: We herein report a novel dual-modal MRI contrast agent, TPE-2Gd, for both magnetic and fluorescence imaging. TPE-2Gd consists of a hydrophobic tetraphenylethene (TPE) fluorophore and two hydrophilic gadolinium (Gd) diethylenetriaminepentaacetic acid moieties. As an amphiphilic molecule, TPE-2Gd aggregates into micelles at a high concentration in aqueous medium. These aggregates are highly emissive, showing an aggregation-induced emission (AIE) characteristic. TPE-2Gd is used as a fluorescent agent for cell imaging, which demonstrates negligible cytotoxicity and excellent photostability owing to its AIE property. As a magnetic resonance imaging (MRI) contrast agent, TPE-2Gd exhibits similar longitudinal relaxivity in water (R1,TPE-2Gd = 3.36 ± 0.10 s(-1) per mM of Gd(3+)) as those commercial agents (e.g., Magnevist, R1,magnevist = 3.70 ± 0.02 s(-1) per mM of Gd(3+)). Compared with Magnevist, the circulation lifetime of TPE-2Gd nanoaggregates in living rats is extended from 10 min to 1 h. With relatively high specificity to the liver, the MR imaging could remain hyperintense in liver even after 150 min post injection. These TPE-2Gd nanoparticles can be excreted gradually via renal filtration due to the disassembly of the nanoparticles into small molecules during circulation. TPE-2Gd could thus potentially be used as a liver specific MRI contrast agent for clinical diagnosis.
authors.affiliation: HKUST Shenzhen Research Institute, No. 9 Yuexing 1st RD, South Area, Hi-tech Park Nanshan, Shenzhen 518057, China.
authors.forename: Yilong
authors.initials: Y
authors.lastname: Chen
authors.forename: Min
authors.initials: M
authors.lastname: Li
authors.forename: Yuning
authors.initials: Y
authors.lastname: Hong
authors.forename: Jacky W Y
authors.initials: JW
authors.lastname: Lam
authors.forename: Qichang
authors.initials: Q
authors.lastname: Zheng
authors.forename: Ben Zhong
authors.initials: BZ
authors.lastname: Tang
mesh_terms: D000818:Animals; D049109:Cell Proliferation; D003287:Contrast Media; D006367:HeLa Cells; D006801:Humans; D008099:Liver / Q000378:metabolism / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D046529:Microscopy, Electron, Transmission; D051381:Rats
chemical_list: D003287:Contrast Media