scholarly journals Probing Reversible Guest Binding with Hyperpolarized 129Xe-NMR: Characteristics and Applications for Cucurbit[n]urils

Molecules ◽  
2020 ◽  
Vol 25 (4) ◽  
pp. 957 ◽  
Author(s):  
Jabadurai Jayapaul ◽  
Leif Schröder
Keyword(s):  
Direct Detection ◽  
Chemical Exchange ◽  
Noble Gas ◽  
Chemical Exchange Saturation Transfer ◽  
Future Directions ◽  
Molecular Switching ◽  
129Xe Nmr ◽  
Guest Binding ◽  
Hyperpolarized 129Xe ◽  
Displacement Assays

Cucurbit[n]urils (CB[n]s) are a family of macrocyclic host molecules that find various applications in drug delivery, molecular switching, and dye displacement assays. The CB[n]s with n = 5–7 have also been studied with 129Xe-NMR. They bind the noble gas with a large range of exchange rates. Starting with insights from conventional direct detection of bound Xe, this review summarizes recent achievements with chemical exchange saturation transfer (CEST) detection of efficiently exchanging Xe in various CB[n]-based supramolecular systems. Unprecedented sensitivity has been reached by combining the CEST method with hyperpolarized Xe, the production of which is also briefly described. Applications such as displacement assays for enzyme activity detection and rotaxanes as emerging types of Xe biosensors are likewise discussed in the context of biomedical applications and pinpoint future directions for translating this field to preclinical studies.

scholarly journals Bacterial spore detection and analysis using hyperpolarized 129Xe chemical exchange saturation transfer (Hyper-CEST) NMR

2014 ◽  
Vol 5 (8) ◽  
pp. 3197-3203 ◽  
Author(s):  
Yubin Bai ◽  
Yanfei Wang ◽  
Mark Goulian ◽  
Adam Driks ◽  
Ivan J. Dmochowski
Keyword(s):  
Bacillus Subtilis ◽  
Nmr Spectroscopy ◽  
Bacillus Anthracis ◽  
Chemical Exchange ◽  
Bacterial Spore ◽  
Chemical Exchange Saturation Transfer ◽  
Saturation Transfer ◽  
Hyperpolarized 129Xe ◽  
Spore Detection

Hyper-CEST 129Xe NMR spectroscopy was employed to detect Bacillus anthracis and Bacillus subtilis spores in solution, and interrogate the layers that comprise their structures.

scholarly journals Molecular Sensing with Host Systems for Hyperpolarized 129Xe

Molecules ◽  
2020 ◽  
Vol 25 (20) ◽  
pp. 4627
Author(s):  
Jabadurai Jayapaul ◽  
Leif Schröder
Keyword(s):  
Chemical Engineering ◽  
Chemical Exchange ◽  
Chemical Exchange Saturation Transfer ◽  
Biophysical Parameters ◽  
Molecular Sensing ◽  
Design And Synthesis ◽  
Transient Nature ◽  
Hyperpolarized 129Xe ◽  
Hydrophobic Binding ◽  
Hyperpolarized Noble Gases

Hyperpolarized noble gases have been used early on in applications for sensitivity enhanced NMR. 129Xe has been explored for various applications because it can be used beyond the gas-driven examination of void spaces. Its solubility in aqueous solutions and its affinity for hydrophobic binding pockets allows “functionalization” through combination with host structures that bind one or multiple gas atoms. Moreover, the transient nature of gas binding in such hosts allows the combination with another signal enhancement technique, namely chemical exchange saturation transfer (CEST). Different systems have been investigated for implementing various types of so-called Xe biosensors where the gas binds to a targeted host to address molecular markers or to sense biophysical parameters. This review summarizes developments in biosensor design and synthesis for achieving molecular sensing with NMR at unprecedented sensitivity. Aspects regarding Xe exchange kinetics and chemical engineering of various classes of hosts for an efficient build-up of the CEST effect will also be discussed as well as the cavity design of host molecules to identify a pool of bound Xe. The concept is presented in the broader context of reporter design with insights from other modalities that are helpful for advancing the field of Xe biosensors.

scholarly journals Binding site exchange kinetics revealed through efficient spin–spin dephasing of hyperpolarized 129Xe

2021 ◽  
Vol 12 (1) ◽  
pp. 158-169
Author(s):  
Martin Kunth ◽  
Leif Schröder
Keyword(s):  
Binding Site ◽  
Chemical Exchange ◽  
Spin Dephasing ◽  
Hyperpolarized 129Xe ◽  
Site Exchange ◽  
Exchange Kinetics ◽  
Displacement Assays

Localized detection of hyperpolarized, exchanging Xe spins enables quantitative insights at unprecedented sensitivity for characterizing chemical exchange kinetics in various contexts such as host–guest interactions and displacement assays.

scholarly journals Nanoparticle-Based Contrast Agents for 129Xe HyperCEST NMR and MRI Applications

2019 ◽  
Vol 2019 ◽  
pp. 1-25 ◽  
Author(s):  
Jabadurai Jayapaul ◽  
Leif Schröder
Keyword(s):  
Optical Pumping ◽  
Spin Exchange ◽  
Chemical Exchange ◽  
Noble Gas ◽  
Chemical Exchange Saturation Transfer ◽  
Spin Exchange Optical Pumping ◽  
Spectral Dispersion ◽  
Low Sensitivity ◽  
Clinical Mri ◽  
Critical Aspects

Spin hyperpolarization techniques have enabled important advancements in preclinical and clinical MRI applications to overcome the intrinsic low sensitivity of nuclear magnetic resonance. Functionalized xenon biosensors represent one of these approaches. They combine two amplification strategies, namely, spin exchange optical pumping (SEOP) and chemical exchange saturation transfer (CEST). The latter one requires host structures that reversibly bind the hyperpolarized noble gas. Different nanoparticle approaches have been implemented and have enabled molecular MRI with 129Xe at unprecedented sensitivity. This review gives an overview of the Xe biosensor concept, particularly how different nanoparticles address various critical aspects of gas binding and exchange, spectral dispersion for multiplexing, and targeted reporter delivery. As this concept is emerging into preclinical applications, comprehensive sensor design will be indispensable in translating the outstanding sensitivity potential into biomedical molecular imaging applications.

Quantitative biosensor detection by chemically exchanging hyperpolarized 129Xe

2018 ◽  
Vol 20 (3) ◽  
pp. 1800-1808 ◽  
Author(s):  
S. Korchak ◽  
T. Riemer ◽  
W. Kilian ◽  
L. Mitschang
Keyword(s):  
Chemical Exchange ◽  
Quantitative Modeling ◽  
Chemical Exchange Saturation Transfer ◽  
Saturation Transfer ◽  
Hyperpolarized 129Xe

Quantitative modeling and evaluation of biosensor detection by hyperpolarized 129Xe chemical exchange saturation transfer (Hyper-CEST).

Amide proton transfer imaging for differentiation of tuberculomas from high-grade gliomas: Preliminary experience

2021 ◽  
pp. 197140092110027
Author(s):  
Karthik Kulanthaivelu ◽  
Shumyla Jabeen ◽  
Jitender Saini ◽  
Sanita Raju ◽  
Atchayaram Nalini ◽  
...  
Keyword(s):  
Proton Transfer ◽  
Chemical Exchange ◽  
Spin Echo ◽  
Chemical Exchange Saturation Transfer ◽  
Amide Proton ◽  
High Grade ◽  
Saturation Pulse ◽  
Amide Proton Transfer ◽  
High Grade Gliomas ◽  
Amide Protons

Purpose Tuberculomas can occasionally masquerade as high-grade gliomas (HGG). Evidence from magnetisation transfer (MT) imaging suggests that there is lower protein content in the tuberculoma microenvironment. Building on the principles of chemical exchange saturation transfer and MT, amide proton transfer (APT) imaging generates tissue contrast as a function of the mobile amide protons in tissue’s native peptides and intracellular proteins. This study aimed to further the understanding of tuberculomas using APT and to compare it with HGG. Method Twenty-two patients ( n = 8 tuberculoma; n = 14 HGG) were included in the study. APT was a 3D turbo spin-echo Dixon sequence with inbuilt B0 correction. A two-second, 2 μT saturation pulse alternating over transmit channels was applied at ±3.5 ppm around water resonance. The APT-weighted image (APTw) was computed as the MT ratio asymmetry (MTRasym) at 3.5 ppm. Mean MTRasym values in regions of interest (areas = 9 mm2; positioned in component with homogeneous enhancement/least apparent diffusion coefficient) were used for the analysis. Results MTRasym values of tuberculomas ( n = 14; 8 cases) ranged from 1.34% to 3.11% ( M = 2.32 ± 0.50). HGG ( n = 17;14 cases) showed MTRasym ranging from 2.40% to 5.70% ( M = 4.32 ± 0.84). The inter-group difference in MTRasym was statistically significant ( p < 0.001). APTw images in tuberculomas were notable for high MTRasym values in the perilesional oedematous-appearing parenchyma (compared to contralateral white matter; p < 0.001). Conclusion Tuberculomas demonstrate lower MTRasym ratios compared to HGG, reflective of a relative paucity of mobile amide protons in the ambient microenvironment. Elevated MTRasym values in perilesional parenchyma in tuberculomas are a unique observation that may be a clue to the inflammatory milieu.

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