title: Temperature response of 129Xe depolarization transfer and its application for ultrasensitive NMR detection.
abstract: Trapping xenon in functionalized cryptophane cages makes the sensitivity of hyperpolarized (HP) 129Xe available for specific NMR detection of biomolecules. Here, we study the signal transfer onto a reservoir of unbound HP xenon by gating the residence time of the nuclei in the cage through the temperature-dependant exchange rate. Temperature changes larger than approximately 0.6 K are detectable as an altered reservoir signal. The temperature response is adjustable with lower concentrations of caged xenon providing more sensitivity at higher temperatures. Ultrasensitive detection of functionalized cryptophane at 310 K is demonstrated with a concentration of 10 nM, corresponding to a approximately 4000-fold sensitivity enhancement compared to conventional detection. This makes HPNMR capable of detecting such constructs in concentrations far below the detection limit of benchtop uv-visible light absorbance.
authors.affiliation: Department of Chemistry, University of California, Berkeley, California 94720, USA. LSchroeder@lbl.gov
authors.forename: Leif
authors.initials: L
authors.lastname: Schröder
authors.forename: Tyler
authors.initials: T
authors.lastname: Meldrum
authors.forename: Monica
authors.initials: M
authors.lastname: Smith
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Lowery
authors.forename: David E
authors.initials: DE
authors.lastname: Wemmer
authors.forename: Alexander
authors.initials: A
authors.lastname: Pines
mesh_terms: D001360:Avidin / Q000737:chemistry; D001710:Biotin / Q000737:chemistry; D046911:Macromolecular Substances / Q000737:chemistry; D019906:Nuclear Magnetic Resonance, Biomolecular / Q000379:methods*; D011083:Polycyclic Compounds; D011506:Proteins / Q000737:chemistry; D012680:Sensitivity and Specificity; D013696:Temperature; D014230:Triazoles / Q000737:chemistry; D014979:Xenon Isotopes / Q000737:chemistry*
chemical_list: D046911:Macromolecular Substances; D011083:Polycyclic Compounds; D011506:Proteins; D014230:Triazoles; D014979:Xenon Isotopes; C523242:cryptophane; D001360:Avidin; D001710:Biotin