Design of a 15N Molecular Unit to Achieve Long Retention of Hyperpolarized Spin State

Hiroshi Nonaka; Masashi Hirano; Yuki Imakura; Yoichi Takakusagi; Kazuhiro Ichikawa; Shinsuke Sando

doi:10.1038/srep40104

Design of a ¹⁵N Molecular Unit to Achieve Long Retention of Hyperpolarized Spin State

Sci Rep. 2017 Jan 9:7:40104. doi: 10.1038/srep40104.

Authors

Hiroshi Nonaka¹, Masashi Hirano², Yuki Imakura¹, Yoichi Takakusagi³, Kazuhiro Ichikawa^{3

4}, Shinsuke Sando¹

Affiliations

¹ Department of Chemistry and Biotechnology, Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
² Department of Applied Chemistry, Graduate School of Engineering, Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka 819-0395, Japan.
³ Incubation Center for Advanced Medical Science, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan.
⁴ Innovation Center for Medical Redox Navigation, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan.

Abstract

Nuclear hyperpolarization is a phenomenon that can be used to improve the sensitivity of magnetic resonance molecular sensors. However, such sensors typically suffer from short hyperpolarization lifetime. Herein we report that [¹⁵N, D₁₄]trimethylphenylammonium (TMPA) has a remarkably long spin-lattice relaxation time (1128 s, 14.1 T, 30 °C, D₂O) on its ¹⁵N nuclei and achieves a long retention of the hyperpolarized state. [¹⁵N, D₁₄]TMPA-based hyperpolarized sensor for carboxylesterase allowed the highly sensitive analysis of enzymatic reaction by ¹⁵N NMR for over 40 min in phophate-buffered saline (H₂O, pH 7.4, 37 °C).

Publication types

Research Support, Non-U.S. Gov't