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Biocompatible Nanocomplexes for Molecular Targeted MRI Contrast Agent

Zhijin Chen1, Dexin Yu2, Shaojie Wang3, Na Zhang1*, Chunhong Ma2 and Zaijun Lu3*

Author Affiliations

1 School of Pharmaceutical Science, Shandong University, 44 Wenhua Xi Road, 250012, Ji’nan, People’s Republic of China

2 Department of Radiology Medicine, Affiliated Qilu Hospital, Shandong University, 44 Wenhua Xi Road, 250012, Ji’nan, People’s Republic of China

3 School of Chemistry and Chemical Engineering, Shandong University, 27 Shanda Road, 250012, Ji’nan, People’s Republic of China

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Nanoscale Research Letters 2009, 4:618-626  doi:10.1007/s11671-009-9286-x

Published: 18 March 2009


Accurate diagnosis in early stage is vital for the treatment of Hepatocellular carcinoma. The aim of this study was to investigate the potential of poly lactic acid–polyethylene glycol/gadolinium–diethylenetriamine-pentaacetic acid (PLA–PEG/Gd–DTPA) nanocomplexes using as biocompatible molecular magnetic resonance imaging (MRI) contrast agent. The PLA–PEG/Gd–DTPA nanocomplexes were obtained using self-assembly nanotechnology by incubation of PLA–PEG nanoparticles and the commercial contrast agent, Gd–DTPA. The physicochemical properties of nanocomplexes were measured by atomic force microscopy and photon correlation spectroscopy. The T1-weighted MR images of the nanocomplexes were obtained in a 3.0 T clinical MR imager. The stability study was carried out in human plasma and the distribution in vivo was investigated in rats. The mean size of the PLA–PEG/Gd–DTPA nanocomplexes was 187.9 ± 2.30 nm, and the polydispersity index was 0.108, and the zeta potential was −12.36 ± 3.58 mV. The results of MRI test confirmed that the PLA–PEG/Gd–DTPA nanocomplexes possessed the ability of MRI, and the direct correlation between the MRI imaging intensities and the nano-complex concentrations was observed (r = 0.987). The signal intensity was still stable within 2 h after incubation of the nanocomplexes in human plasma. The nanocomplexes gave much better image contrast effects and longer stagnation time than that of commercial contrast agent in rat liver. A dose of 0.04 mmol of gadolinium per kilogram of body weight was sufficient to increase the MRI imaging intensities in rat livers by five-fold compared with the commercial Gd–DTPA. PLA–PEG/Gd–DTPA nanocomplexes could be prepared easily with small particle sizes. The nanocomplexes had high plasma stability, better image contrast effect, and liver targeting property. These results indicated that the PLA–PEG/Gd–DTPA nanocomplexes might be potential as molecular targeted imaging contrast agent.

Nanocomplexes; Molecular imaging; Magnetic resonance imaging; DTPA–Gd; PLA–PEG