NMR applications to living cells requires that the cells remain viable and metabolically active during the duration of the NMR measurement to preserve the biological significance of the experiment. Typical in-cell NMR experiments are performed under static sample conditions, and are limited to few hours of experimental time to avoid compromising cell viability. Moreover, even in that short time frame, the metabolic homeostasis of the cells is not maintained, due to changes in the chemical composition of the external medium. To overcome this limitation, NMR bioreactors have been developed, in which a flow system provides fresh nutrients and removes metabolic by-products while the cell sample is kept confined within the NMR active volume. In addition to the existing custom-made designs, a modular design was developed at CERM/CIRMMP in collaboration with Bruker UK Ltd. that allows multiple flow unit configurations, including in-cell NMR bioreactor suitable for a high density of cells, either in suspension or immobilized in a gel matrix. The main technical limitations of current bioreactor designs are: a reduced sample volume / number of cells compared to static in-cell NMR, leading to decreased S/N ratio and prolonged acquisition times, and a relatively long and complex assembly procedure, which can cause cellular stress prior actual in-cell NMR measurements, compromising metabolic homeostasis and cell viability. These aspects need to be optimized to allow widespread application of in-cell NMR bioreactors to real-time monitoring of biological processes. The ultimate goal of this JRA is to implement and standardise a bioreactor setup that is broadly applicable (i.e. can be adapted to any type of in-cell NMR sample) and routinely accessible by non-expert users.