Biological J-Coupling Spectroscopy at Low Magnetic Field.

Nuclear magnetic resonance (NMR) spectroscopy is a powerful tool for investigating biological systems. In particular, low-field NMR offers advantages for studying cellular metabolism in their native environment. This is especially relevant for in vitro studies, where low-field NMR can be used to analyze biological samples with reduced equipment size and cost, potentially enabling high-throughput benchtop research. However, the study of cellular metabolism at low, milli-Tesla, magnetic fields remains an unsolved challenge due to reduced chemical shifts and dominant spin-spin couplings (J-couplings) that complicate spectral analysis. Herein, this problem is tackled by combining J-coupling spectroscopy and parahydrogen-induced polarization with a multinuclear scanner built in-house. The results demonstrate the ability to resolve pyruvate metabolism of cancer cells in regular NMR tubes at milli-Tesla fields using [2-13C]pyruvate. This work concludes that low-field biological J-coupling spectroscopy can be a valuable tool for studying cellular metabolism, enabling new insights into biological systems.