Synthesis of Long-T1 Silicon Nanoparticles for Hyperpolarized 29Si Magnetic Resonance Imaging

TL;DR

This paper reports the synthesis and characterization of silicon nanoparticles with long T1 relaxation times for use as hyperpolarized MRI agents, demonstrating their potential for enhanced imaging.

Contribution

It introduces a new synthesis method for silicon nanoparticles with long T1 times suitable for hyperpolarized MRI applications.

Findings

Particles have ~10 nm diameter with T1 > 600 s

Particles retain hyperpolarization after DNP

Surface functionalization achieved with various ligands

Abstract

We describe the synthesis, materials characterization and dynamic nuclear polarization (DNP) of amorphous and crystalline silicon nanoparticles for use as hyperpolarized magnetic resonance imaging (MRI) agents. The particles were synthesized by means of a metathesis reaction between sodium silicide (Na4Si4) and silicon tetrachloride (SiCl4) and were surface functionalized with a variety of passivating ligands. The synthesis scheme results in particles of diameter ~10 nm with long size-adjusted 29Si spin lattice relaxation (T1) times (> 600 s), which are retained after hyperpolarization by low temperature DNP.