Open Access Nano Express

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

Abstract

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.

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