Engineering a small, near-infrared (NIR) plasmonic nanostructure for both imaging and therapy is a critical nanomedical challenge. Recently, we demonstrated that the plasmonic core-shell nanostructure consisting of Au core, SiO<sub>2 </sub>spacing layer, and outer Au shell, known as nanomatryoshkas (NM), is a highly promising compact nanostructure with a NIR photothermal therapeutic response. Here, we demonstrate that near-infrared-resonant NM can provide simultaneous contrast enhancement for both T1 magnetic resonance imaging (MRI) and fluorescence optical imaging (FOI) by simultaneously encapsulating various contrast agents in the internal silica layer between the Au core and shell. The internalization of Gd(III)-DOTA within the NM would reduce potential exposure of Gd(III) in future clinical applications, ameliorating mounting Gd(III) toxicity concerns while enhancing MRI contrast. Here we also demonstrate that this method of T1 enhancement is even more effective for Fe(III) DOTA doped within NM. Fe(III)NM are found to have relaxivities 2× greater than those found in the widely used gadolinium chelate, Gd(III) DOTA, providing a practical alternative that would eliminate Gd(III) patient exposure entirely. The photobleaching rate of the fluorescent dye is also significantly reduced when sequestered within NM, potentially lengthening the viable imaging time. This multifunctional nanostructure could enable not only tissue visualization aided by MRI but also fluorescence-based nanoparticle tracking for quantifying nanoparticle distributions in vivo, in addition to a near-infrared photothermal therapeutic response.

Designing a compact plasmonic nanoparticle with enhanced fluorescence and potentially safer T1 magnetic imaging contrast

2019 Fall National Meeting

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