Associate Professor Pernille Rose Jensen, Center for Hyperpolarization & Metabolism, Department of Health Technology, DTU

Hyperpolarized ¹³C-NMR for In-Cell metabolism

Hyperpolarization with the dissolution dynamic nuclear polarization (dDNP) technique yields >10,000-fold signal increases for NMR-active nuclei (e.g. ¹³C). Hyperpolarized ¹³C-labeled metabolic tracer molecules thus allow real-time observations of biochemical pathways in living cellular systems without interfering background. This methodology lends itself to the direct observation of altered intracellular reaction chemistry imparted for instance by drug treatment, infections or other diseases. A reoccurring challenge for longitudinal cell studies of mammalian cells with NMR and dDNP-NMR is maintaining cell viability in the high field NMR spectrometer.

In a proof-of-concept study we show that sustaining the cell cultivation in cell incubators and only transferring the cells to the NMR spectrometer for the few minutes required for the dDNP-NMR measurements is an attractive alternative to cell maintenance in the NMR tube. Our most recent approach use tailored NMR coils matched to microfluidic cell chambers. This strategy further minimizes cell manipulation upon metabolic measurements combined with optimal growth conditions for adhering cells. In-Cell NMR is currently a relatively small research field with unfulfilled potential and increasing impact. Technical solutions to proper cell maintenance combined with new strategies for improved NMR sensitivity will hopefully provide the robustness and sensitivity needed to consolidate this non-invasive analytical approach for metabolic profiling.