Encapsulation of Gadolinium Oxide Nanoparticle (Gd2O3) Contrasting Agents in PAMAM Dendrimer Templates for Enhanced Magnetic Resonance Imaging in Vivo

• Published in: ACS applied materials & interfaces Vol. 9; no. 8; pp. 6782 - 6795
• Main Authors: Mekuria, Shewaye Lakew, Debele, Tilahun Ayane, Tsai, Hsieh-Chih
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 01.03.2017
• Subjects: Contrast Media; Dendrimers; Gadolinium; Magnetic Resonance Imaging; Metal Nanoparticles; T 1−T 2 magnetic resonance imaging; in vivo; longitudinal relaxation; PAMAM dendrimer; gadolinium oxide (Gd2O3); T1−T2 magnetic resonance imaging
• ISSN: 1944-8244; 1944-8252
• DOI: 10.1021/acsami.6b14075

There has been growing interest in the research of nanomaterials for biomedical applications in recent decades. Herein, a simple approach to synthesize the G4.5-Gd2O3-poly­(ethylene glycol) (G4.5-Gd2O3-PEG) nanoparticles (NPs) that demonstrate potential as dual (T 1 and T 2) contrasting agents in magnetic resonance imaging (MRI) has been reported in this study. Compared to the clinically popular Gd-DTPA contrasting agents, G4.5-Gd2O3-PEG NPs exhibited a longer longitudinal relaxation time (T 1) and better biocompatibility when incubated with macrophage cell line RAW264.7 in vitro. Furthermore, the longitudinal relaxivity (r 1) of G4.5-Gd2O3-PEG NPs was 53.9 s–1 mM–1 at 7T, which is equivalent to 4.8 times greater than to the Gd-DTPA contrasting agents. An in vivo T 1-weighted MRI results revealed that G4.5-Gd2O3-PEG NPs significantly enhanced signals in the intestines, kidney, liver, bladder, and spleen. In addition, the T 2-weighted MRI results revealed darker contrast in the kidney, which proves that G4.5-Gd2O3-PEG NPs can be exploited as T 1 and T 2 contrasting agents. In summary, these findings suggest that the G4.5-Gd2O3-PEG NPs synthesized by an alternative approach can be used as dual MRI contrasting agents.