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Start Over Author "Ahmad MW" Topic magnetic resonance imaging
2 results on '"Ahmad MW"'

1. In Vivo Positive Magnetic Resonance Imaging Applications of Poly(methyl vinyl ether-alt-maleic acid)-coated Ultra-small Paramagnetic Gadolinium Oxide Nanoparticles.

Author

Ahmad MY, Ahmad MW, Yue H, Ho SL, Park JA, Jung KH, Cha H, Marasini S, Ghazanfari A, Liu S, Tegafaw T, Chae KS, Chang Y, and Lee GH

Subjects
Animals, Cell Line, Tumor, Cell Survival, Chemical Phenomena, Contrast Media, Mice, Molecular Structure, Particle Size, Signal-To-Noise Ratio, Spectrum Analysis, Coated Materials, Biocompatible chemistry, Gadolinium chemistry, Magnetic Resonance Imaging methods, Maleic Anhydrides chemistry, Metal Nanoparticles chemistry, Metal Nanoparticles ultrastructure, Polyvinyls chemistry
Abstract

The study of ultra-small paramagnetic gadolinium oxide (Gd 2 O 3 ) nanoparticles (NPs) as in vivo positive (T 1 ) magnetic resonance imaging (MRI) contrast agents is one of the most attractive fields in nanomedicine. The performance of the Gd 2 O 3 NP imaging agents depends on the surface-coating materials. In this study, poly(methyl vinyl ether-alt-maleic acid) (PMVEMA) was used as a surface-coating polymer. The PMVEMA-coated paramagnetic ultra-small Gd 2 O 3 NPs with an average particle diameter of 1.9 nm were synthesized using the one-pot polyol method. They exhibited excellent colloidal stability in water and good biocompatibility. They also showed a very high longitudinal water proton spin relaxivity (r 1 ) value of 36.2 s -1 mM -1 (r 2 /r 1 = 2.0; r 2 = transverse water proton spin relaxivity) under a 3.0 tesla MR field which is approximately 10 times higher than the r 1 values of commercial molecular contrast agents. High positive contrast enhancements were observed in in vivo T 1 MR images after intravenous administration of the NP solution sample, demonstrating its potential as a T 1 MRI contrast agent.

Published
2020
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2. Surface coated Eu(OH)3 nanorods: a facile synthesis, characterization, MR relaxivities and in vitro cytotoxicity.

Author

Kattel K, Park JY, Xu W, Bony BA, Heo WC, Tegafaw T, Kim CR, Ahmad MW, Jin S, Baeck JS, Chang Y, Kim TJ, Bae JE, Chae KS, Jeong JY, and Lee GH

Subjects
Cell Line, Tumor, Coated Materials, Biocompatible chemical synthesis, Coated Materials, Biocompatible toxicity, Contrast Media chemical synthesis, Contrast Media toxicity, Europium, Humans, Hydroxides chemical synthesis, Materials Testing, Metal Nanoparticles chemistry, Nanotubes chemistry, Cell Survival drug effects, Hydroxides toxicity, Magnetic Resonance Imaging methods, Metal Nanoparticles toxicity, Nanotubes toxicity
Abstract

The water-soluble and biocompatible D-glucuronic acid coated Eu(OH)3 nanorods (average thickness x average length = 9.0 x 118.3 nm) have been prepared in one-pot synthesis. The D-glucuronic acid coated Eu(OH)3 nanorods showed a strong fluorescence at approximately 600 nm with a narrow emission band width. A cytotoxicity test by using DU145 cells showed that D-glucuronic acid coated Eu(OH)3 nanorods are not toxic up to 100 microM, making them a promising candidate for biomedical applications such as fluorescent imaging. The minimum Eu concentration needed for a conventional confocal imaging was estimated to be approximately 0.1 mM. Therefore, D-glucuronic acid coated Eu(OH)3 nanorods can be applied to fluorescent imaging. However, a very tiny magnetization of approximately 1.2 emu/g at room temperature and at an applied field of 5 tesla was observed. As a result, very small r1 and r2 water proton relaxivities were estimated, implying that surface coated Eu(OH)3 nanorods are not sufficient for MRI contrast agents.

Published
2013
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