NMR is an indispensable tool in science and medicine. The sensitivity of NMR, however, is less competitive due to small magnetic moments of nuclei and thus small Zeeman energy splitting. The goal of this research is to develop novel hyperpolarization techniques for solid state NMR spectroscopy operable at room temperature with general solid state biomaterials. Currently, the most prominent way to generate enhanced nuclear polarization in solid state NMR is dynamic nuclear polarization (DNP) with gyrotrons. DNP is a process that electron polarization is transferred to nuclei;therefore maximum theoretical enhancement of NMR signal determined by gyromagnetic ratio, gammae/gammaN~658 for 1H), is expected. Our new approach employs optical nuclear polarization technique (optical excitation, subsequently triplet state quenching by stable radical and the transfer of electron polarization to nuclei). Since the optical excitation is a non-thermal process, NMR signal enhancement can greatly exceed the traditional DNP ceiling (gammae/gammaN). Upon successful development of this technique, we expect to provide the following improvements over the current status of solid state NMR: 1) significant reduction in measurement time (which will lead to the study of higher molecular weight biopolymers), 2) improved detection limit, and 3) hyperpolarization at high temperature in an ambient sample condition. Among many research areas that can benefit from enhanced sensitivity, we expect the tissue metabolomics and metabolism study with biopsy will be greatly influenced.
NMR is less competitive compared to other tools in biomedicine because of poor sensitivity. We are developing novel hyperpolarization techniques that can significantly improve the sensitivity of solid-state NMR spectroscopy using optical nuclear polarization.
