Abstract
Bioresorbable medical devices once implanted into the body are "invisible" to imaging techniques such as X-ray/fluoroscopy and magnetic resonance imagining (MRI). Prior attempts to produce radiopaque polymers have limited success due to their inability to generate homogeneous mixtures of polymer and contrast agent without subsequent alterations in polymer structure. Here we investigate a novel approach in which a MRI contrast medium, gadodiamide, can be used as a polymerization initiator in poly(propylene fumarate) (PPF) synthesis to achieve a radiopaque and MRI-visible polymer poly(gadodiamide fumaric acid) (PGFA). With this method polymer structure, thermal properties, and rheological behavior are conserved with no prior manipulation to monomer units necessary. This unique polymer in combination with poly(lactic-co-glycolic acid) (PLGA) can be formulated into MRI-visible nanoparticles with drug delivery potential. This novel polymer in both liquid and nanoparticle form enables new possibilities in medical device and drug delivery design.