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.
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