Enhancing T-1 magnetic resonance imaging contrast with internalized gadolinium(III) in a multilayer nanoparticle

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Marangoni, Valeria S. ; Neumann, Oara ; Henderson, Luke ; Kaffes, Caterina C. ; Zhang, Hui ; Zhang, Runmin ; Bishnoi, Sandra ; Ayala-Orozco, Ciceron ; Zucolotto, Valtencir ; Bankson, James A. ; Nordlander, Peter ; Halas, Naomi J.

• Document type: Journal article
• Source: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA; v. 114, n. 27, p. 6960-6965, JUL 3 2017.
• Web of Science Citations: 29

Abstract

Multifunctional nanoparticles for biomedical applications have shown extraordinary potential as contrast agents in various bioimaging modalities, near-IR photothermal therapy, and for light-triggered therapeutic release processes. Over the past several years, numerous studies have been performed to synthesize and enhance MRI contrast with nanoparticles. However, understanding the MRI enhancement mechanism in a multishell nanoparticle geometry, and controlling its properties, remains a challenge. To systematically examine MRI enhancement in a nanoparticle geometry, we have synthesized MRI-active Au nanomatryoshkas. These are Au coresilica layer-Au shell nanoparticles, where Gd(III) ions are encapsulated within the silica layer between the inner core and outer Au layer of the nanoparticle (Gd-NM). This multifunctional nanoparticle retains its strong near-IR Fano-resonant optical absorption properties essential for photothermal or other near-IR light-triggered therapy, while simultaneously providing increased T-1 contrast in MR imaging by concentrating Gd(III) within the nanoparticle. Measurements of Gd-NM revealed a strongly enhanced T-1 relaxivity (r(1) similar to 24 mM(-1).s(-1)) even at 4.7 T, substantially surpassing conventional Gd(III) chelating agents (r(1) similar to 3 mM(-1).s(-1) at 4.7 T) currently in clinical use. By varying the thickness of the outer gold layer of the nanoparticle, we show that the observed relaxivities are consistent with Solomon-Bloembergen-Morgan (SBM) theory, which takes into account the longer-range interactions between the encapsulated Gd(III) and the protons of the H2O molecules outside the nanoparticle. This nanoparticle complex and its MRI T-1-enhancing properties open the door for future studies on quantitative tracking of therapeutic nanoparticles in vivo, an essential step for optimizing light-induced, nanoparticle-based therapies. (AU)

• FAPESP's process: 14/13645-2 - Development of cell-membrane coatings for the stealth delivery of MRI-active nanoparticles
• Grantee: Valéria Spolon Marangoni
• Support type: Scholarships abroad - Research Internship - Doctorate