From spherical to osmotically shrunken paramagnetic liposomes: an improved generation of LIPOCEST MRI agents with highly shifted water protons

The advent of the molecular imaging era prompts the search for innovative imaging probes to set up novel procedures for pursuing early diagnosis and efficient follow-up of therapeutic treatments. The results reported here represent a substantial step ahead in the field of the MRI contrast agents based on the CEST mechanism. This new generation of imaging probes couples the outstanding sensitivity displayed by the previous generation of spherical LIPOCEST agents to a significantly extended range of accessible irradiation frequency values, which are approaching those typical for PARACEST agents. Interestingly, preliminary results indicated that the stability and the sensitivity of the shrunken LIPOCEST probes are comparable to those of the spherical parent agents.