New long circulating magnetoliposomes as contrast agents for detection of ischemia-reperfusion injuries by MRI

New long circulating magnetoliposomes coated with polyethylene glycol (PEG), and loaded with PEG-coated 10 nm superparamagnetic iron oxide nanoparticles (SPION), were developed. The magnetoliposomes relaxivities r1 ,r 2 measured in a magnetic field of 7 T showed a minor effect on T1, but a major effect on T2. These nanosystems were used as a negative contrast agent for MRI in a nonclinical study to visualize, in a rat model of liver ischemia, ischemia–reperfusion injuries. Magnetic resonance micro-images (MRM) at 7 T were obtained for rat liver with and without magnetoliposomes administration and analyzed in comparison with liver biomarkers and histological results. These new long circulating magnetoliposomes enhanced the detection of lesions indicating their potential use as efficient MRI negative contrast agent for the detection of liver ischemia–reperfusion injuries.