Available online 16 September 2022

To expand the single-dose duration over which noninvasive clinical and preclinical cancer imaging can be conducted with high sensitivity, and well-defined spatial and temporal resolutions, a facile strategy to prepare ultrasmall nanoparticulate X-ray contrast media (nano-XRCM) as dual-modality imaging agents for positron emission tomography (PET) and computed tomography (CT) has been established. Synthesized from controlled copolymerization of triiodobenzoyl ethyl acrylate and oligo(ethylene oxide) acrylate monomers, the amphiphilic statistical iodocopolymers (ICPs) could directly dissolve in water to afford thermodynamically stable solutions with high aqueous iodine concentrations (>140 mg iodine/mL water) and comparable viscosities to conventional small molecule XRCM. The formation of ultrasmall iodinated nanoparticles with hydrodynamic diameters of ca. 10 nm in water was confirmed by dynamic and static light scattering techniques. In a breast cancer mouse model, in vivo biodistribution studies revealed that the 64Cu-chelator-functionalized iodinated nano-XRCM exhibited extended blood residency and higher tumor accumulation compared to typical small molecule imaging agents. PET/CT imaging of tumor over 3 days showed good correlation between PET and CT signals, while CT imaging allowed continuous observation of tumor retention even after 10 days post-injection, enabling longitudinal monitoring of tumor retention for imaging or potentially therapeutic effect after a single administration of nano-XRCM.

64Cu-Chelator-functionalized amphiphilic statistical iodocopolymer (DOTA-ICP) enabled ultrasmall 64Cu-DOTA-ICP nanoparticulate X-ray contrast media (nano-XRCM). The longitudinal monitoring of tumor retention by noninvasive preclinical PET/CT imaging with high sensitivity, and well-defined spatial and temporal resolutions were realized after a single administration of nano-XRCM at ∼2 mg iodine/kg dose.Download : Download high-res image (196KB)Download : Download full-size image

Amphiphilic statistical iodocopolymer

CT

X-ray contrast media

Ultrasmall nanoassembly

PET/CT

Longitudinal tumor monitoring

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