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Geometrical confinement of gadolinium-based contrast agents in nanoporous particles enhances T1 contrast

2010; Nature Portfolio; Volume: 5; Issue: 11 Linguagem: Inglês

10.1038/nnano.2010.203

1748-3395

Jeyarama S. Ananta, Biana Godin, Richa Sethi, Loïck Moriggi, Xuewu Liu, Rita E. Serda, Ramkumar Krishnamurthy, Raja Muthupillai, Robert D. Bolskar, Lothar Helm, Mauro Ferrari, Lon J. Wilson, Paolo Decuzzi,

Advanced NMR Techniques and Applications

Magnetic resonance imaging contrast agents are currently designed by modifying their structural and physiochemical properties to improve relaxivity and to enhance image contrast. Here, we show a general method for increasing relaxivity by confining contrast agents inside the nanoporous structure of silicon particles. Magnevist, gadofullerenes and gadonanotubes were loaded inside the pores of quasi-hemispherical and discoidal particles. For all combinations of nanoconstructs, a boost in longitudinal proton relaxivity r1 was observed: Magnevist, r1 ≈ 14 mM−1 s−1/Gd3+ ion (∼8.15 × 10+7 mM−1 s−1/construct); gadofullerenes, r1 ≈ 200 mM−1 s−1/Gd3+ ion (∼7 × 10+9 mM−1 s−1/construct); gadonanotubes, r1 ≈ 150 mM−1 s−1/Gd3+ ion (∼2 × 10+9 mM−1 s−1/construct). These relaxivity values are about 4 to 50 times larger than those of clinically available gadolinium-based agents (∼4 mM−1 s−1/Gd3+ ion). The enhancement in contrast is attributed to the geometrical confinement of the agents, which influences the paramagnetic behaviour of the Gd3+ ions. Thus, nanoscale confinement offers a new and general strategy for enhancing the contrast of gadolinium-based contrast agents. Confining gadolinium-based contrast agents inside the porous structure of silicon microparticles can improve their T1 contrast, offering a general approach for developing highly efficient MRI contrast agents.