Three-dimensional microchannel reflecting cell size distribution for on-chip production of platelet-like particles

Recently, microfluidic bioreactors that trap injected megakaryocytes (MKs) by application of fluid force to them have been proposed as small test benches to evaluate the in vitro platelet production process. However, making a flow rate constant after trapping MKs remains a challenge and bottleneck because the cross-sectional area of the microchannel decreases due to the trapped MKs. Therefore, we present a microfluidic bioreactor containing a three-dimensional microchannel that has been designed based on the cell size distribution of immortalized megakaryocyte cell lines (imMKCLs). As results, we succeeded in trapping imMKCLs with small variations in the cross-sectional area along the flow path. Through experiments on on-chip production of platelet-like particles (PLPs) for 12 h using imMKCLs derived from human-induced pluripotent stem cells, we found that the average number of the total produced PLPs per imMKCLs was 23, 24, 16, and 14 when the applied pressures was 10, 50, 100 and 200 kPa, respectively. From these results, we confirmed that the proposed microfluidic bioreactor can be applied as a test bench for evaluating of the on-chip PLP production.