Liposomes with conjugates of a calix[4]arene and a Gd-DOTA derivative on the outside surface; an efficient potential contrast agent for MRI

Paramagnetic liposomes used as contrast agents in magnetic resonance imaging (MRI) often suffer from low efficacies because of slow water diffusion through the membrane. We present an approach to overcome this limitation by incorporation of a calix[4]arene based agent that expresses the chelates towards the bulk water.