Hyperpolarized 129Xe can be used in cell suspensions using two different strategies:
- Alone, as a free diffusive tracer. Xenon enters in the cells in ~30 ms without losing its hyper-polarization. Xenon interacting with living cells gives rise to a specific NMR signal in the 200 ppm region. The chemical shift and the intensity of this signal are correlated to the nature of the cell line, the viability and density.
- Encapsulated in a host molecule to detect a specific biological mechanism, for instance, the internalization process of transferrin. The biosensor has been obtained by the grafting of cryptophane moieties to the transferrin.