Human pluripotent stem cell‐derived endothelial cells (hPSC‐ECs) present an attractive alternative to primary EC sources for vascular grafting. However, there is a need to mature them towards either an arterial or venous subtype. A vital environmental factor involved in the arteriovenous specification of ECs during early embryonic development is fluid shear stress; therefore, there have been attempts to employ adult arterial shear stress conditions to mature hPSC‐ECs. However, hPSC‐ECs are naïve to fluid shear stress, and their shear responses are still not well understood. Here, we used a multiplex microfluidic platform to systematically investigate the dose‐time shear responses on hPSC‐EC morphology and arterial‐venous phenotypes over a range of magnitudes coincidental with physiological levels of embryonic and adult vasculatures. The device comprised of six parallel cell culture chambers that were individually linked to flow‐setting resistance channels, allowing us to simultaneously apply shear stress ranging from 0.4 to 15 dyne/cm 2. We found that hPSC‐ECs required up to 40 hr of shear exposure to elicit a stable phenotypic change. Cell alignment was visible at shear stress <1 dyne/cm 2, which was independent of shear stress magnitude and duration of exposure. We discovered that the arterial markers NOTCH1 and EphrinB2 exhibited a dose‐dependent increase in a similar manner beyond a threshold level of 3.8 dyne/cm 2, whereas the venous markers COUP‐TFII and EphB4 expression remained relatively constant across different magnitudes. These findings indicated that hPSC‐ECs were sensitive to relatively low magnitudes of shear stress, and a critical level of ~4 dyne/cm 2 was sufficient to preferentially enhance their maturation into an arterial phenotype for future vascular tissue engineering applications.

The front cover image is based on the Article Determination of critical shear stress for maturation of human pluripotent stem cell‐derived endothelial cells towards an arterial subtype by Seep Arora et al., DOI: https://doi.org/10.1002/bit.26910.