High Polarization of Nuclear Spins Mediated by Nanoparticles at Millikelvin Temperatures

David G. Gadian¹, David T. Peat², Kelvin Goh², Anthony J. Horsewill², John R. Owers-Bradley²

Our goal was to use the brute-force approach (exposure to low temperature and high magnetic field) to achieve high polarizations of nuclei such as 13C and 15N, with a view to using pre-polarized 13C- or 15N-labelled agents to probe tissue metabolism in vivo. We explored the possibility that selected nanoparticles (including metallic nanoparticles) might act as low temperature relaxation agents. We found that with the use of copper nanoparticles we were able to achieve very high (>10%) 13C polarization levels in realistic periods of time. This methodology will enable us to generate and store large-scale quantities of highly polarized materials.