129Xe NMR overview of xenon physisorbed in porous solids

Springuel‐Huet, Marie‐Anne; Bonardet, J.L.; Gédéon, A.; Fraissard, J.

doi:10.1002/(sici)1097-458x(199912)37:13<s1::aid-mrc578>3.0.co;2-x

Cited by 73 publications

(52 citation statements)

References 114 publications

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“…Changes in the rotational and vibrational motions of the cryptophane cage caused by binding to the protein could also affect the xenon chemical shift. Xenon has long been used as a probe of cavity size, structure, and occupancy in microporous materials (14,(27)(28)(29). Indeed, the sensitivity of xenon to perturbations of the cage is so great that deuteration of one methyl group results in a readily discernible change in the bound xenon chemical shift (17).…”

Section: Figmentioning

confidence: 99%

“…Laserpolarized xenon is being developed as a diagnostic agent for medical magnetic resonance imaging (9) and spectroscopy (10) and as a probe for the investigation of surfaces and cavities in porous materials and biological systems. Xenon provides information both through direct observation of its NMR spectrum (11)(12)(13)(14)(15)(16)(17) and by the transfer of its enhanced polarization to surrounding spins (18,19). In a protein solution, weak xenonprotein interactions render the chemical shift of xenon dependent on the accessible protein surface and even allow the monitoring of the protein conformation (20).…”

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confidence: 99%

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Functionalized xenon as a biosensor

Spence

Rubin

Dimitrov

et al. 2001

Proc. Natl. Acad. Sci. U.S.A.

306

325

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The detection of biological molecules and their interactions is a significant component of modern biomedical research. In current biosensor technologies, simultaneous detection is limited to a small number of analytes by the spectral overlap of their signals. We have developed an NMR-based xenon biosensor that capitalizes on the enhanced signal-to-noise, spectral simplicity, and chemical-shift sensitivity of laser-polarized xenon to detect specific biomolecules at the level of tens of nanomoles. We present results using xenon ''functionalized'' by a biotin-modified supramolecular cage to detect biotin-avidin binding. This biosensor methodology can be extended to a multiplexing assay for multiple analytes.R ecent biosensor technologies exploit surface plasmon resonance (1), fluorescence polarization (2), and fluorescence resonance energy transfer (3) as detection methods. Although the sensitivity of such techniques is excellent, extending these assays to multiplexing capabilities has proven challenging because of the difficulty in distinguishing signals from different binding events. Although NMR spectroscopy is able to finely resolve signals from different molecules and environments, the spectral complexity and low sensitivity of NMR spectroscopy normally preclude its use as a detector of molecular targets in complex mixtures. Notable successes (4, 5) in the application of NMR to such problems are still limited by long acquisition times or a limited number of detectable analytes. Laser-polarized xenon NMR benefits from good signal-to-noise and spectral simplicity with the added advantage of substantial chemical-shift sensitivity.Optical pumping (6) has enhanced the use of xenon as a sensitive probe of its molecular environment (7,8). Laserpolarized xenon is being developed as a diagnostic agent for medical magnetic resonance imaging (9) and spectroscopy (10) and as a probe for the investigation of surfaces and cavities in porous materials and biological systems. Xenon provides information both through direct observation of its NMR spectrum (11)(12)(13)(14)(15)(16)(17) and by the transfer of its enhanced polarization to surrounding spins (18,19). In a protein solution, weak xenonprotein interactions render the chemical shift of xenon dependent on the accessible protein surface and even allow the monitoring of the protein conformation (20). To use xenon as a specific sensor of molecules, it would be valuable to ''functionalize'' the xenon for the purpose of reporting specific interactions with a molecular target.In this report, we demonstrate an example of such a functionalized system that exhibits molecular target recognition. Fig. 1 shows the chemical principle used for our initial study, a biosensor molecule designed to bind both xenon and protein.The molecule consists of three parts: the cage, which contains the xenon; the ligand, which directs the functionalized xenon to a specific protein; and the tether, which links the ligand and the cage. The ligand and target can be any two molecules or constructs. In su...

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Section: Figmentioning

confidence: 99%

mentioning

confidence: 99%

Functionalized xenon as a biosensor

Spence

Rubin

Dimitrov

et al. 2001

Proc. Natl. Acad. Sci. U.S.A.

306

325

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“…NMR studies of materials such as porous media [17], solution [10,[18][19][20], and tissue (including in-vivo applications [11,12] and the xenon biosensor) by means of inclusion of sensor nuclei into the matrix inherently suffer from low signal-to-noise because the majority of the volume in the detection region is occupied by the matrix material itself. The guest sensor occupies only a small fraction of the total sample volume, resulting in a low coil filling factor or low magnetization, and thus decreased sensitivity.…”

Section: Introductionmentioning

confidence: 99%

Remotely detected high-field MRI of porous samples

Seeley

Han

Pines

2004

Journal of Magnetic Resonance

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Remote detection of NMR is a novel technique in which an NMR-active sensor surveys an environment of interest and retains memory of that environment to be recovered at a later time in a different location. The NMR or MRI information about the sensor nucleus is encoded and stored as spin polarization at the first location and subsequently moved to a different physical location for optimized detection. A dedicated probe incorporating two separate radio frequency (RF) -circuits was built for this purpose. The encoding solenoid coil was large enough to fit around the bulky sample matrix, while the smaller detection solenoid coil had not only a higher quality factor but also an enhanced filling factor since the coil volume comprised purely the sensor nuclei. We obtained two-dimensional (2D) void space images of two model porous samples with resolution less than 1.4 mm 2 . The remotely-reconstructed images demonstrate the ability to determine fine structure with image quality superior to their directly detected counterparts and show the great potential of NMR remote detection for imaging applications that suffer from low sensitivity due to low concentrations and filling factor.

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“…In vivo MRI of airways with hp 129 Xe as a contrast agent (19)(20)(21) suffers from a lower sensitivity compared with hp 3 He. However, 129 Xe adds a further parameter not available by 3 He, namely, the chemical shift that allows for insights into the local environment of the xenon atoms (22)(23)(24)(25)(26)(27). The 129 Xe chemical shift has been used extensively for research in materials science, engineering, and xenon dissolved in liquids including human blood (3,5,6,8,9,12,28).…”

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confidence: 99%

Hyperpolarized krypton-83 as a contrast agent for magnetic resonance imaging

Pavlovskaya

Cleveland

Stupic

et al. 2005

Proc. Natl. Acad. Sci. U.S.A.

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For the first time, magnetic resonance imaging (MRI) with hyperpolarized (hp) krypton-83 ( 83 Kr) has become available. The relaxation of the nuclear spin of 83 Kr atoms (I ‫؍‬ 9͞2) is driven by quadrupolar interactions during brief adsorption periods on surrounding material interfaces. Experiments in model systems reveal that the longitudinal relaxation of hp 83 Kr gas strongly depends on the chemical composition of the materials. The relaxationweighted contrast in hp 83 Kr MRI allows for the distinction between hydrophobic and hydrophilic surfaces. The feasibility of hp 83 Kr MRI of airways is tested in canine lung tissue by using krypton gas with natural abundance isotopic distribution. Additionally, the influence of magnetic field strength and the presence of a breathable concentration of molecular oxygen on longitudinal relaxation are investigated.NMR ͉ optical pumping ͉ pulmonary ͉ MRI ͉ xenon H igh nuclear spin polarization in noble gasses can be generated through rubidium vapor spin exchange optical pumping (RbSEOP) (1) and allows for NMR signal enhancements of many orders of magnitude (2). Hyperpolarized (hp) 3 He and hp 129 Xe (both I ϭ 1͞2) have both been used in a wide range of NMR and magnetic resonance imaging (MRI) experiments that are otherwise impossible (3-15). In particular hp 3 He has been applied for medical MRI diagnosis of pulmonary diseases (16)(17)(18)(19). One of the fundamental parameters with high diagnostic value for hp 3 He MRI is the spin-density that is a result of the helium concentration in a particular volume. Spin-density mapping of hp 3 He can be applied to visualize ventilation in lungs. Other useful parameters are 3 He diffusion that provides information about alveolar size distributions in lung tissue and hp 3 He relaxation that depends on oxygen partial pressure in lungs. In vivo MRI of airways with hp 129 Xe as a contrast agent (19-21) suffers from a lower sensitivity compared with hp 3 He. However, 129 Xe adds a further parameter not available by 3 He, namely, the chemical shift that allows for insights into the local environment of the xenon atoms (22-27). The 129 Xe chemical shift has been used extensively for research in materials science, engineering, and xenon dissolved in liquids including human blood (3,5,6,8,9,12,28). The chemical shift obtained from hp 129 Xe can be used to generate an in vivo MRI contrast that is a probe for gas perfusion in lungs (i.e., exchange of the gaseous xenon with the lung parenchyma) (29).3 He and 129 Xe are the only spin I ϭ 1͞2 stable isotopes of the noble gas group, but there are three more NMR active isotopes in this group with higher spin that possess a nuclear electric quadrupole moment. The three quadrupolar isotopes are 21 Ne (I ϭ 3͞2, natural abundance 0.27%), 83 Kr (I ϭ 9͞2, natural abundance 11.5%), and 131 Xe (I ϭ 3͞2, natural abundance 21%). Quadrupolar interactions in these noble gas atoms cause spin relaxation and coherent spin evolution that are probes for the shape, size, and symmetry of void spaces as well as the ...

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129Xe NMR overview of xenon physisorbed in porous solids

Cited by 73 publications

References 114 publications

Functionalized xenon as a biosensor

Functionalized xenon as a biosensor

Remotely detected high-field MRI of porous samples

Hyperpolarized krypton-83 as a contrast agent for magnetic resonance imaging

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