Hyperpolarized Nanodiamond with Long Spin Relaxation Times

TL;DR

This paper demonstrates that hyperpolarized 13C spins in synthetic nanodiamond can achieve long relaxation times exceeding one hour, enabling enhanced magnetic resonance imaging without toxic radicals.

Contribution

It introduces a method to hyperpolarize 13C in nanodiamond with relaxation times over an hour, surpassing previous short-lived agents and expanding theranostic applications.

Findings

13C in nanodiamond can be hyperpolarized at room temperature

Relaxation times exceed 1 hour in solid-state nanodiamond

No toxic free-radicals are needed for hyperpolarization

Abstract

The use of hyperpolarized agents in magnetic resonance (MR), such as 13C-labeled compounds, enables powerful new imaging and detection modalities that stem from a 10,000-fold boost in signal. A major challenge for the future of the hyperpolarizaton technique is the inherently short spin relaxation times, typically < 60 seconds for 13C liquid-state compounds, which limit the time that the signal remains boosted. Here, we demonstrate that 1.1% natural abundance 13C spins in synthetic nanodiamond (ND) can be hyperpolarized at cryogenic and room temperature without the use of toxic free- radicals, and, owing to their solid-state environment, exhibit relaxation times exceeding 1 hour. Combined with the already established applications of NDs in the life-sciences as inexpensive fluorescent markers and non-cytotoxic substrates for gene and drug delivery, these results extend the theranostic capabilities of nanoscale diamonds into the domain of hyperpolarized MR.