Bioreactor in-cell NMR: A powerful tool for observing intracellular biological events

Unlike conventional biochemical and cell biological methods, in-cell NMR enables direct observation of intracellular protein structures and dynamics at atomic resolution in their native cellular environment. However, a key challenge is maintaining cell viability during prolonged measurements, as nutrient depletion leads to rapid cell death and protein degradation. To address this, bioreactor systems have been developed to perfuse culture media, enabling long-term NMR experiments. Bioreactor-based in-cell NMR has enabled real-time observation of function-related structural information of proteins, which are involved in various intracellular events, such as signal transduction, oxidative stress responses, and glycolytic regulation. Additionally, in-cell NMR has been applied to drug discovery, allowing assessment of drug binding kinetics, intracellular permeability, and target engagement within living cells.