Researchers from the University of Tokyo have developed a new approach to enhance magnetic resonance imaging (MRI) sensitivity using fullerenes as polarizing agents. MRI is widely used in medical diagnostics, but its ability to detect certain molecules is limited by current technology.
Dynamic nuclear polarization (DNP) is a technique that can improve MRI clarity by modifying target molecules, but it typically requires special crystalline materials and polarizing agents that are difficult to produce. The research team demonstrated that fullerenes, also known as buckyballs—3D carbon structures—can serve as effective polarizing agents for DNP.
The method involves modifying fullerenes so they remain polarized and then using light to activate them. When these modified fullerenes, referred to as trans-3a isomers, are introduced into a sample, their electrons transfer spin polarization to nearby atomic nuclei. This results in stronger signals for MRI sensors.
Graduate student Kieta Sakamoto explained: "The polarization of the targets is done outside the body. After polarization, the sample is dissolved, and the fullerene, which could be harmful, is removed before injection into a hypothetical patient." Sakamoto added: "Because this method, triplet-DNP, avoids the need for a liquid helium coolant, it can run on much simpler, lower-cost equipment. It also makes it possible to bulk-polarize diagnostic chemical probes like pyruvate or anticancer drugs that conventional MRI cannot detect. Our next goal is to develop biocompatible matrices so we can hyperpolarize such medically important molecules. We plan to demonstrate high-sensitivity MRI in animal models first. If those experiments succeed and clinical trials follow, we expect this technology could reach real medical settings in about 10 to 20 years."
This development may lead to broader applications for MRI technology by allowing detection of molecules not currently visible with standard techniques.
