Dynamic nuclear polarisation can make MRI dramatically more sensitive, but conventional implementations demand specialised crystalline samples, awkward polarising agents, cryogenic temperatures and high magnetic fields. A team including University of Tokyo researchers, led by Nobuhiro Yanai, has shown that fullerenes, the football-shaped carbon molecules known as buckyballs, can serve as light-driven polarising agents that work without that forbidding infrastructure.
The researchers modified fullerene isomers so they remain rigid and hold their polarisation. Illumination polarises the molecules' electrons, which pass the alignment on to nearby atomic nuclei, strengthening the magnetic resonance signal. In a disordered, glass-like sample the team achieved a polarisation of 14.2 percent, comfortably above the roughly 10 percent threshold generally considered necessary for biological applications before the signal decays.
Crucially, polarisation happens outside the body, the sample is dissolved, and the fullerene removed before any injection, while the method avoids liquid helium entirely. Reported in Nature Communications, the advance could eventually allow hyperpolarised probes such as pyruvate to be prepared on simpler, cheaper equipment, extending metabolic MRI to many more clinics. The team's roadmap runs through biocompatible matrices and animal studies, with clinical use a long-term prospect.