Tailored nanodiamonds for hyperpolarized 13C MRI

TL;DR

This study demonstrates enhanced and long-lasting hyperpolarized 13C MRI signals in tailored nanodiamonds by controlling defect centers, advancing nanodiamond-based imaging for biological applications.

Contribution

It introduces specific surface treatment protocols that improve 13C polarization and elucidates the role of nitrogen defect centers in nanodiamond core polarization behavior.

Findings

Enhanced 13C polarization achieved in tailored nanodiamonds.

Long-lived polarization signals suitable for imaging.

Identification of nitrogen defect centers as key to polarization.

Abstract

Nanodiamond is poised to become an attractive material for hyperpolarized 13C MRI if large nuclear polarizations can be achieved without the accompanying rapid spin-relaxation driven by paramagnetic species. Here we report enhanced and long-lived 13C polarization in synthetic nanodiamonds tailored by acid-cleaning and air-oxidation protocols. Our results separate the contributions of different paramagnetic species on the polarization behavior, identifying the importance of substitutional nitrogen defect centers in the nanodiamond core. These results are likely of use in the development of nanodiamond-based imaging agents with size distributions of relevance for examining biological processes.