Block Copolymer-Based Gadolinium Nanoparticles as MRI Contrast Agents with High T 1 Relaxivity

AIMS: To synthesize block copolymer-based gadolinium nanoparticles (Gd-NPs) and evaluate their potential as a new MRI contrast agent. MATERIALS & METHODS: The Gd-NPs were developed through coordination of gadolinium chelates into a pentablock copolymer synthesized by two sequential atom transfer radical polymerizations, and evaluated by measuring their T1 relaxivity in vitro and imaging their T1 contrast in tissue using MRI. RESULTS: Solution and MRI studies demonstrated that these Gd-NPs exhibit remarkably high T1 relaxivity on both per particle and per gadolinium ion basis, and can generate a much better MRI contrast compared with gadolinium chelates alone. CONCLUSION: These novel Gd-NPs may have important applications in magnetic resonance-based medical imaging.