Human lymphocytes cultured in 3-D bioreactors: Influence of configuration on metabolite transport and reactions

Peripheral blood lymphocytes isolated from healthy human donors' buffy coat were cultured in membrane bio-reactors (MBR) designed in two different configurations: a conventional hollow-fiber (HF) bundle of modified polyetheretherketone (PEEK-WC) arranged in parallel, and a cross-assembled PEEK-WC and polyethersulfone (PES) HF membranes having different structural properties. Both bioreactors were experimentally compared in terms of metabolic activity of cultured cells, monitored over 8 days with respect to glucose uptake rate (GUR) and lactate production rate (LPR), and mathematically modelled by Computational Fluid Dynamics (CFD) method in order to investigate the impact of geometrical configuration and transport properties of biomaterials. The almost uniform trend of GUR from day 2 to day 7 (average of 0.0497 ± 0.0076 ng/h cell) and the low LPR (that decreased from an initial value of 2.92 ± 0.0055 pg/h cell to practically zero at day 8) provided evidence for superior performance of crossed-HFMBR in reproducing an optimal in vitro physiological environment with quite uniform concentration distribution of species in the extracellular space of the bioreactor and able to maintain lymphocyte viability and functions. The crossed HFMBR also resulted in an enhanced production of interleukin IL-2 over 8 days (average of 0.995 ± 0.25 pg/h/Mcell) and IL-10 in the first 3 days (average of 6.46 ± 0.28 pg/h/Mcell) which were up to one order of magnitude higher with respect to values measured in the parallel configuration.