Short-chain PEG molecules strongly bound to magnetic nanoparticle for MRI long circulating agents

PEG covalently bound to DMSA-coated magnetic nanoparticles reduces surface charge and maintains hydrodynamic size below 100 nm. PEG-coated nanoparticles did not alter HeLa cell viability and were not internalized by cells in contrast to DMSA-coated NP, leading to long NP circulation time in blood of rats and rabbits, which makes this material ideal for use in in vivo imaging systems.