Competitive Displacement Restores the Hyperpolarized N NMR Signal in Blood Plasma.

ACS Phys Chem Au

Advanced Imaging Research Center, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, Texas 75390, United States.

Published: March 2023

Hyperpolarized (HP) NMR can improve the sensitivity of conventional NMR experiments by several orders of magnitude, thereby making it feasible to detect the signal of low sensitivity nuclei such as C and N nuclei in vivo. Hyperpolarized substrates are usually administered by direct injection into the bloodstream, and interaction with serum albumin can cause rapid decay of the hyperpolarized signal due to the shortening of the spin-lattice (T) relaxation time. Here we report that the N T of N labeled, partially deuterated tris(2-pyridylmethyl)amine decreases dramatically upon binding to albumin to such an extent that no HP- signal could be detected. We also demonstrate that the signal could be restored using a competitive displacer, iophenoxic acid, which binds stronger to albumin than tris(2-pyridylmethyl)amine. The methodology presented here eliminates the undesirable effect of albumin binding and should widen the range of hyperpolarized probes for in vivo studies.

Download full-text PDF

Source
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC10037449PMC
http://dx.doi.org/10.1021/acsphyschemau.2c00059DOI Listing

Publication Analysis

Top Keywords

hyperpolarized nmr
8
hyperpolarized
5
signal
5
competitive displacement
4
displacement restores
4
restores hyperpolarized
4
nmr signal
4
signal blood
4
blood plasma
4
plasma hyperpolarized
4

Similar Publications

The antibiotic metronidazole (MNZ) has gained interest as a potential MRI contrast agent for imaging hypoxia. N-labeled MNZ can be efficiently hyperpolarized via SABRE-SHEATH (Signal Amplification By Reversible Exchange in SHield Enables Alignment Transfer to Heteronuclei), but the envisioned MRI approach requires that MNZ rapidly undergoes structural changes in hypoxic environments with significant N frequency differences manifested in its downstream metabolic products. We have performed NMR studies of the anticipated metabolic product amino-MNZ (despite anticipated stability concerns) accompanied by computational density functional theory (DFT) studies to predict the N chemical shifts of different relevant species.

View Article and Find Full Text PDF

RF Heating Effects in CEST NMR with Hyperpolarized 129Xe Considering Different Spin Exchange Kinetics and Saturation Schemes.

Chemphyschem

January 2025

Deutsches Krebsforschungszentrum, Translational Molecular Imaging, Im Neuenheimer Feld 223, 69120, Heidelberg, GERMANY.

Chemical exchange saturation transfer (CEST) improves the sensitivity of NMR but depending on the spin exchange kinetics, it can require substantial RF energy deposition to label magnetization. Potential side effects like RF-induced heating may occur and must be monitored. Here, we explore the parameter space considering not only undesired heating but efficient CEST build-up (depolarization rate), spectral resolution (line width), and subsequent effects like changes in chemical shifts of CEST responses must be considered, too.

View Article and Find Full Text PDF

Ultrasensitive Xe Magnetic Resonance Imaging: From Clinical Monitoring to Molecular Sensing.

Adv Sci (Weinh)

January 2025

Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance Spectroscopy and Imaging, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences-Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, 430071, China.

Magnetic resonance imaging (MRI) is a cornerstone technology in clinical diagnostics and in vivo research, offering unparalleled visualization capabilities. Despite significant advancements in the past century, traditional H MRI still faces sensitivity limitations that hinder its further development. To overcome this challenge, hyperpolarization methods have been introduced, disrupting the thermal equilibrium of nuclear spins and leading to an increased proportion of hyperpolarized spins, thereby enhancing sensitivity by hundreds to tens of thousands of times.

View Article and Find Full Text PDF

Nuclear magnetic resonance (NMR) spectroscopy is a valuable diagnostic tool limited by low sensitivity due to low nuclear spin polarization. Hyperpolarization techniques, such as dissolution dynamic nuclear polarization, significantly enhance sensitivity, enabling real-time tracking of cellular metabolism. However, traditional high-field NMR systems and bioreactor platforms pose challenges, including the need for specialized equipment and fixed sample volumes.

View Article and Find Full Text PDF

Nuclear magnetic resonance is extremely attractive for operando studies of chemical reactors. However, the heterogeneous catalyst particles placed inside an NMR probe greatly affect the uniformity of the magnetic field. This problem is especially acute when studying heterogeneous hydrogenation processes using parahydrogen.

View Article and Find Full Text PDF

Want AI Summaries of new PubMed Abstracts delivered to your In-box?

Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!