Deuterated Nanopolymers for Renal and Lymphatic Imaging via Quantitative Deuterium MRI

Abstract

Deuterium (²H) MRI is an emerging tool for noninvasive imaging. We explore the integration of ²H MRI with deuterated multifunctional nanopolymers for deuterated particle imaging (DPI). To this end, amine-terminated G5-polyamidoamine (PAMAM) dendrimers were labeled with deuterated acetyl surface groups, leading to highly ²H-loaded bioparticles, making them ideal for imaging studies. The accumulation of ∼5 nm PAMAM dendrimers in the kidneys could then be seen by ²H MRI with high submillimeter resolution. The natural abundance HDO signal provided an internal concentration reference to these measurements, leading to quantitative dynamic maps showing distinct nanopolymer uptakes within the renal compartments. Further, these nanopolymers allowed us to obtain in vivo maps of activity in the lymph nodes in an inflammatory rodent leg model, demonstrating these deuterated nanopolymers’ potential as a novel class of contrast agents for the quantitative mapping of physiological processes.