Differentiation of embryonic stem cells into cardiomyocytes in a compliant microfluidic system.

The differentiation process of murine embryonic stem cells into cardiomyocytes was investigated with a compliant microfluidic platform which allows for versatile cell seeding arrangements, optical observation access, long-term cell viability, and programmable uniaxial cyclic stretch. Specifically, two environmental cues were examined with this platform--culture dimensions and uniaxial cyclic stretch. First, the cardiomyogenic differentiation process, assessed by a GFP reporter driven by the α-MHC promoter, was enhanced in microfluidic devices (µFDs) compared with conventional well-plates. The addition of BMP-2 neutralizing antibody reduced the enhancement observed in the µFDs and the addition of exogenous BMP-2 augmented the cardiomyogenic differentiation in well plates. Second, 24 h of uniaxial cyclic stretch at 1 Hz and 10% strain on day 9 of differentiation was found to have a negative impact on cardiomyogenic differentiation. This microfluidic platform builds upon an existing design and extends its capability to test cellular responses to mechanical strain. It provides capabilities not found in other systems for studying differentiation, such as seeding embryoid bodies in 2D or 3D in combination with cyclic strain. This study demonstrates that the microfluidic system contributes to enhanced cardiomyogenic differentiation and may be a superior platform compared with conventional well plates. In addition to studying the effect of cyclic stretch on cardiomyogenic differentiation, this compliant platform can also be applied to investigate other biological mechanisms.