ChipNMR: Hyperpolarized NMR for Noninvasive Metabolic Flux Analysis in Perfused Microfluidic Chips

Dissolution dynamic nuclear polarization NMR Spectroscopy (dDNP-NMR) has become a transformative tool for metabolic studies by significantly enhancing signal sensitivity more than 3 orders of magnitude compared to traditional NMR. However, NMR detection probes are optimized for round narrow glass tubes typically 5 mm in diameter, which impose constraints on their utility for metabolic studies of adherent cells. Here, we present a novel NMR probe head integrated with a custom microfluidic chip that facilitates real-time monitoring of hyperpolarized substrate conversion from adherent cells. This system enables metabolic flux analysis in a controlled, in vitro environment, as demonstrated by tracking the conversion of [1-¹³C]pyruvate to [1-¹³C]lactate in HeLa cells over 48 h. The custom microfluidic chip design is modular and adaptable allowing expansion to two-chamber chips, demonstrating its potential in applications for more complex cellular models, such as organ-on-a-chip systems.