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Novel radical‐responsive MRI contrast agent based on paramagnetic liposomes
Author(s) -
Gløgård Christian,
Stensrud Gry,
Aime Silvio
Publication year - 2003
Publication title -
magnetic resonance in chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0749-1581
DOI - 10.1002/mrc.1208
Subject(s) - chemistry , liposome , dithiothreitol , moiety , gadolinium , chelation , thiol , linker , radical , conjugated system , in vivo , cysteine , combinatorial chemistry , photochemistry , stereochemistry , organic chemistry , biochemistry , polymer , microbiology and biotechnology , computer science , biology , enzyme , operating system
Abstract A novel, radical responsive MRI contrast agent based on a gadolinium chelate conjugated to a liposome through a disulfide linker was synthesized, with the aim of pursuing the in vivo mapping of radicals. The liposome was prepared by incorporating a thiol‐activated phospholipid, which was subsequently reacted with a gadolinium chelate containing a free thiol group. The long reorientational motion of the supramolecular adduct endows the paramagnetic agent with a relaxivity significantly higher than that of the free complex. The disulfide bond represents a radical‐sensitive moiety and a large decrease in contrast efficacy ( T 1 relaxivity) is shown upon its cleavage. A preliminary assessment of the system was made by means of in vitro gamma‐irradiation and thiol–disulfide bond exchange with dithiothreitol. Both methods showed a clear dose‐dependent decrease in T 1 ‐relaxivity. Copyright © 2003 John Wiley & Sons, Ltd.