title: Molecular Sensing with Hyperpolarized (129) Xe Using Switchable Chemical Exchange Relaxation Transfer.
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.
authors.affiliation: Centre for Biomolecular Sciences, School of Chemistry, University of Nottingham, Nottingham, NG7 2RD (United Kingdom).
authors.forename: Francesco
authors.initials: F
authors.lastname: Zamberlan
authors.affiliation: Sir Peter Mansfield Imaging Centre, Division of Respiratory Medicine, School of Medicine, University of Nottingham, Nottingham, NG7 2RD (United Kingdom).
authors.forename: Clémentine
authors.initials: C
authors.lastname: Lesbats
authors.affiliation: Sir Peter Mansfield Imaging Centre, Division of Respiratory Medicine, School of Medicine, University of Nottingham, Nottingham, NG7 2RD (United Kingdom).|Current address: Department of Chemistry, Durham University, South Road, Durham, DH1 3LE, United Kingdom.
authors.forename: Nicola J
authors.initials: NJ
authors.lastname: Rogers
authors.affiliation: Centre for Biomolecular Sciences, School of Chemistry, University of Nottingham, Nottingham, NG7 2RD (United Kingdom).
authors.forename: James L
authors.initials: JL
authors.lastname: Krupa
authors.affiliation: Sir Peter Mansfield Imaging Centre, Division of Respiratory Medicine, School of Medicine, University of Nottingham, Nottingham, NG7 2RD (United Kingdom).
authors.forename: Galina E
authors.initials: GE
authors.lastname: Pavlovskaya
authors.affiliation: Centre for Biomolecular Sciences, School of Chemistry, University of Nottingham, Nottingham, NG7 2RD (United Kingdom). Neil.Thomas@Nottingham.ac.uk.
authors.forename: Neil R
authors.initials: NR
authors.lastname: Thomas
authors.affiliation: Sir Peter Mansfield Imaging Centre, Division of Respiratory Medicine, School of Medicine, University of Nottingham, Nottingham, NG7 2RD (United Kingdom). Henryk.Faas@Nottingham.ac.uk.|Sir Peter Mansfield Imaging Centre, Division of Clinical Neuroscience, School of Medicine, University of Nottingham, Nottingham, NG7 2UH (United Kingdom). Henryk.Faas@Nottingham.ac.uk.
authors.forename: Henryk M
authors.initials: HM
authors.lastname: Faas
authors.affiliation: Sir Peter Mansfield Imaging Centre, Division of Respiratory Medicine, School of Medicine, University of Nottingham, Nottingham, NG7 2RD (United Kingdom). Thomas.Meersmann@Nottingham.ac.uk.
authors.forename: Thomas
authors.initials: T
authors.lastname: Meersmann
mesh_terms: D015374:Biosensing Techniques; D003287:Contrast Media / Q000737:chemistry*; D056831:Coordination Complexes / Q000737:chemistry; D006571:Heterocyclic Compounds / Q000737:chemistry; D008279:Magnetic Resonance Imaging; D009942:Organometallic Compounds / Q000737:chemistry; D011083:Polycyclic Compounds / Q000737:chemistry; D014979:Xenon Isotopes / Q000737:chemistry
chemical_list: D003287:Contrast Media; D056831:Coordination Complexes; D006571:Heterocyclic Compounds; D009942:Organometallic Compounds; D011083:Polycyclic Compounds; D014979:Xenon Isotopes; C523242:cryptophane; C050823:gadolinium 1,4,7,10-tetraazacyclododecane-N,N',N'',N'''-tetraacetate
keywords: MRI contrast agent; cryptophane; hyperCEST; hyperpolarized xenon biosensor; molecular imaging