Issue 31, 2016

Impact of Ho3+-doping on 13C dynamic nuclear polarization using trityl OX063 free radical

Abstract

We have investigated the effects of Ho-DOTA doping on the dynamic nuclear polarization (DNP) of [1-13C] sodium acetate using trityl OX063 free radical at 3.35 T and 1.2 K. Our results indicate that addition of 2 mM Ho-DOTA on 3 M [1-13C] sodium acetate sample in 1 : 1 v/v glycerol : water with 15 mM trityl OX063 improves the DNP-enhanced 13C solid-state nuclear polarization by a factor of around 2.7-fold. Similar to the Gd3+ doping effect on 13C DNP, the locations of the positive and negative 13C maximum polarization peaks in the 13C microwave DNP sweep are shifted towards each other with the addition of Ho-DOTA on the DNP sample. W-band electron spin resonance (ESR) studies have revealed that while the shape and linewidth of the trityl OX063 ESR spectrum was not affected by Ho3+-doping, the electron spin–lattice relaxation time T1 of trityl OX063 was prominently reduced at cryogenic temperatures. The reduction of trityl OX063 electron T1 by Ho-doping is linked to the 13C DNP improvement in light of the thermodynamic picture of DNP. Moreover, the presence of Ho-DOTA in the dissolution liquid at room temperature has negligible reduction effect on liquid-state 13C T1, in contrast to Gd3+-doping which drastically reduces the 13C T1. The results here suggest that Ho3+-doping is advantageous over Gd3+ in terms of preservation of hyperpolarized state—an important aspect to consider for in vitro and in vivo NMR or imaging (MRI) experiments where a considerable preparation time is needed to administer the hyperpolarized 13C liquid.

Graphical abstract: Impact of Ho3+-doping on 13C dynamic nuclear polarization using trityl OX063 free radical

Article information

Article type
Paper
Submitted
07 Jun 2016
Accepted
13 Jul 2016
First published
13 Jul 2016

Phys. Chem. Chem. Phys., 2016,18, 21351-21359

Impact of Ho3+-doping on 13C dynamic nuclear polarization using trityl OX063 free radical

A. Kiswandhi, P. Niedbalski, C. Parish, P. Kaur, A. Martins, L. Fidelino, C. Khemtong, L. Song, A. D. Sherry and L. Lumata, Phys. Chem. Chem. Phys., 2016, 18, 21351 DOI: 10.1039/C6CP03954E

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements