Dynamic Real-Time Magnetic Resonance at Very Low Magnetic Fields

The phenomenon of nuclear magnetic resonance (NMR) is widely applied in biomedical and biological science to study structures and dynamics of proteins and their reactions. Despite its impact, NMR is an inherently insensitive phenomenon and has driven the field to construct spectrometers with increasingly higher magnetic fields leading to more detection sensitivity. Here, we are demonstrating that enzymatic reactions can be followed in real-time at millitesla fields, 1000-fold lower than state-of-the-art spectrometers. This requires signal-enhancing samples via hyperpolarization. Within seconds, we have enhanced the signals of 2- 13Cpyruvate, an important metabolite to probe cancer metabolism, in 22 mM concentrations (up to 10.1%±0.1% polarization) and show that such a large signal allows for the real-time detection of enzymatic conversion of pyruvate to lactate. This development paves the pathways for biological studies in portable and affordable NMR systems with a potential for medical diagnostics.