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Molecular Sensing with Hyperpolarized 129 Xe Using Switchable Chemical Exchange Relaxation Transfer
Author(s) -
Zamberlan Francesco,
Lesbats Clémentine,
Rogers Nicola J.,
Krupa James L.,
Pavlovskaya Galina E.,
Thomas Neil R.,
Faas Henryk M.,
Meersmann Thomas
Publication year - 2015
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.201500367
Subject(s) - paramagnetism , chemistry , xenon , relaxation (psychology) , solvent , gadolinium , molecule , chemical shift , chemical physics , nuclear magnetic resonance , organic chemistry , psychology , social psychology , physics , quantum mechanics
Abstract An approach for hyperpolarized 129 Xe molecular sensors is explored using paramagnetic relaxation agents that can be deactivated upon chemical or enzymatic reaction with an analyte. Cryptophane encapsulated 129 Xe within the vicinity of the paramagnetic center experiences fast relaxation that, through chemical exchange of xenon atoms between cage and solvent pool, causes accelerated hyperpolarized 129 Xe signal decay in the dissolved phase. In this proof‐of‐concept work, the relaxivity of Gadolinium III ‐DOTA on 129 Xe in the solvent was increased eightfold through tethering of the paramagnetic molecule to a cryptophane cage. This potent relaxation agent can be ′turned off′ specifically for 129 Xe through chemical reactions that spatially separate the Gd III centre from the attached cryptophane cage. Unlike 129 Xe chemical shift based sensors, the new concept does not require high spectral resolution and may lead to a new generation of responsive contrast agents for molecular MRI.