Multilamellar LipoCEST Agents Obtained from Osmotic Shrinkage of Paramagnetically Loaded Giant Unilamellar Vescicles (GUVs)

Martina Tripepi; Giuseppe Ferrauto; Paolo Oronzo Bennardi; Silvio Aime; Daniela Delli Castelli

doi:10.1002/anie.201912327

Multilamellar LipoCEST Agents Obtained from Osmotic Shrinkage of Paramagnetically Loaded Giant Unilamellar Vescicles (GUVs)

Angew Chem Int Ed Engl. 2020 Feb 3;59(6):2279-2283. doi: 10.1002/anie.201912327. Epub 2020 Jan 3.

Authors

Martina Tripepi¹, Giuseppe Ferrauto¹, Paolo Oronzo Bennardi¹, Silvio Aime¹, Daniela Delli Castelli¹

Affiliation

¹ Department of Molecular Biotechnology and Health Sciences, University of Torino, Via Nizza 52, 10126, Torino, Italy.

PMID: 31803970
DOI: 10.1002/anie.201912327

Abstract

Moving from nano- to micro-systems may not just be a matter of scale, but it might imply changes in the properties of the systems that can open new routes for the development of efficient MRI contrast agents. This is the case reported in the present paper, where giant liposomes (giant unilamellar vesicles, GUVs) loaded with Ln^III complexes have been studied as chemical exchange saturation transfer (CEST) MRI contrast agents. The comparison between nanosized liposomes (small unilamellar vesicles, SUVs) and GUVs sharing the same formulation led to differences that could not be accounted for only in terms of the increase in size (from 100-150 nm to 1-2 μm). Upon osmotic shrinkage, GUVs yielded a saturation-transfer effect three order of magnitude higher than SUVs consistent with the increase in vesicles volume. Confocal microscopy showed that the shrinkage of GUVs resulted in multilamellar particles whereas SUVs are known to yield asymmetrical, discoidal shape.

Keywords: imaging agents; lanthanides; lipoCEST; liposomes; vesicles.