Chelating systems complexed with metal or metal ions are used as contrast agent or radiotracers in nuclear imaging. Here, we have developed two DTPA-based imaging systems. DTPA was incorporated into a pH-sensitive polymer, which can function as an imaging agent with enhanced degradability to reduce toxicity associated with long circulation time. DTPA-modified crosslinkers were also synthesized and used to form hydrogel nanoparticles, which could function as both delivery and imaging system. Here, we have chelated both agents with Gd and assessed their performance as MRI contrast agents. Both agents were found to have higher relaxivity than clinically used agent, Magnevist. In vivo imaging revealed that our polymer has rapid clearance, and provides comparable contrast enhancement as Magnevist at only half the clinical dose. By changing the chelator, different metal ions can be incorporated, and these imaging agents can be used in different imaging modalities.

pH-degradable polymer MRI contrast agent and hydrogel nanoparticle as trackable delivery system

243rd National Meeting (2012)

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