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Quantitative Assessment of Xenon Exchange Kinetics with Cucurbit[6]uril in Physiological Saline
Author(s) -
Korchak Sergey,
Riemer Thomas,
Kilian Wolfgang,
Mitschang Lorenz
Publication year - 2018
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.201800048
Subject(s) - xenon , chemistry , kinetics , supramolecular chemistry , biosensor , cucurbituril , nuclear magnetic resonance spectroscopy , analytical chemistry (journal) , chemical physics , stereochemistry , molecule , chromatography , organic chemistry , biochemistry , physics , quantum mechanics
Cucurbit[6]uril and xenon form supramolecular complexes that are of great potential for biosensing by NMR. This host‐guest system acts alike a signaler in sensors facilitating the ultrasensitive detection of biomarkers by saturation transfer of chemically exchanging, hyperpolarized 129 Xe. Here, the exchange process is evaluated by NMR exchange spectroscopy utilizing the preparation of anti‐parallel longitudinal magnetization with respect to free and host‐bound xenon and the variation of xenon concentration. Evidence for dissociative as well as degenerate exchange mechanisms is revealed by a linear regression analysis of the determined exchange rates resulting in rate coefficients of 1131±11 s −1 (2390±70 s −1 ) and 108500±4900 M −1 s −1 (174200±13900 M −1 s −1 ), respectively, and an affinity constant of 289±8 M −1 (278±14 M −1 ) in physiological saline at 298 K (310 K). The results elucidate the supramolecular exchange and underpin the high efficacy for biosensing of this host‐guest system. The approach is generally applicable to enhanced host‐xenon exchange dynamics, yet slow on the NMR timescale, for quantitative kinetics and biosensing analyses.