A Cone-Plate Bioreactor for Applying Physiologically Derived Shear Stress Waveforms to Study Endothelial Mechanotransduction and Cardiac Cell Signaling

Fluid shear stress is a critical regulator of endothelial cell function and cardiovascular development, yet in vitro platforms often lack the ability to reproduce physiologically relevant, time-dependent flow environments with quantitative precision. Here, we present the design and validation of a macro-scale cone-plate bioreactor engineered to deliver controlled steady and pulsatile shear stress waveforms to endothelial monolayers and engineered tissues. The system integrates a geometry optimized to minimize secondary flow effects, a feedback-controlled motor capable of reproducing complex waveforms, and a viscosity-informed control framework to account for shear-dependent fluid behavior. Using this platform, endothelial cells were exposed to steady and physiologically derived pulsatile shear stresses. Cells exhibited increased alignment and eccentricity under shear, confirming biologically relevant mechanical stimulation. While pulsatile shear did not significantly alter endothelial neuregulin-1 expression, exogenous administration studies revealed a nonlinear, dose-dependent increase in cardiomyocyte proliferation. Furthermore, co-culture experiments demonstrated that shear-conditioned endothelial cells promote cardiomyocyte proliferation, suggesting a mechanotransduction-mediated paracrine signaling mechanism. Together, these results establish a versatile and quantitatively controlled platform for studying cardiovascular mechanobiology. This device enables systematic investigation of shear-dependent cellular responses and provides a foundation for integrating co-culture systems and three-dimensional engineered tissues under physiologically relevant hemodynamic conditions.