Abstract
The need to develop specific magnetic nanostructures for resonance imaging becomes more evident by the day. In this study, iron oxide magnetic nanoparticles stabilized with ethylenediaminetetraacetic acid (EDTA), followed by a gadolinium (Gd) ion chelation reaction Gd-EDTA-MNPs were synthesized and evaluated as a potential magnetic resonance imaging contrast agent. The contrast agent has been developed by a facile and universal coordination chemistry method. The compositions, structures, as well as the physicochemical characterization techniques, are reported. Fourier-transform infrared spectroscopy and X-ray photoelectron spectroscopy demonstrate the success of gadolinium complexation by the carboxyl group of EDTA coated iron oxide nanoparticles. Cytotoxicity measurements have been performed using a cell culture of normal human keratinocytes (HaCaT cell line) and human malignant melanoma (A375). Our results show a significant increase in the transverse relaxivity induced by the complexation with gadolinium, 540 mM−1 s−1 for Gd-EDTA-MNPs. The longitudinal relaxation dispersion curves show one order of magnitude enhancement of the longitudinal relaxivity from 2.2 mM−1 s−1 (EDTA-MNPs) to 29.6 mM−1 s−1 (Gd-EDTA-MNPs) at a 20 MHz resonance frequency. The results suggest that Gd complexation may represent a viable approach in obtaining contrast agents able to reduce both T1 and T2 nuclear relaxation times.
Acknowledgments
We thank Dr. Sesarman Alina from Babes-Bolyai University for the HaCaT cell line gift.