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

Significance We demonstrate a magnetic resonance image-enhancing nanoparticle with the potential for use in multiple biomedical imaging and therapeutic applications. The nanoparticle contains internal gadolinium ions for T1 imaging contrast, located between an inner core and outer Au layer, in a multilayered geometry. The proton relaxivity is enhanced through longer-range interactions with the protons outside the nanoparticle, a radical departure from the molecular chelates currently in use for MRI. This geometry provides a very large relaxivity enhancement (r1 ∼ 24 mM−1 ⋅s−1 ) compared with conventional chelating agents (Gd-DOTA: r1 ∼ 3 mM−1 ⋅s−1 ) at high magnetic fields (4.7 T). This MRI-enhancing nanoparticle geometry opens opportunities for the development of multifunctional MRI-active nanoparticles for biomedical applications.