Engineering a Mechanical Stimulation System for Inducing Shear Stress in Chondrocyte Cultures

This paper presents the development of a
mechanical stimulation system designed for chondrocyte cell
culture, specifically aimed at applying controlled shear stress to
chondrocyte cells grown on a 12-well plate. Understanding the
impact of shear stress on chondrocytes requires careful
observation of the regulation of key proteins, including collagen
type I, collagen type II, and aggrecan. The stimulation system is
engineered to deliver intermittent fluid shear stress within the
range of 0.3 to 1 Pa, achieved through the movement of a
piezoelectric stack actuator. The system accommodates a 12-well
cell culture plate and features a 12-probe fluid shear stirrer that
operates at a frequency of 30 Hz. In operation, the stirrer exerts
pressure on the culture media, inducing oscillatory motion that
generates fluid shear stress. To evaluate the performance of the
mechanical stimulation system, we experimentally varied the
probe displacement at increments of 2.91, 16.19, 28.31, 39.56,
and 42.43 μm. The corresponding velocities were measured at
178.6, 1495, 2515, 3741, and 4821 μm/s. These observed
displacement and velocity values were then theoretically
converted to shear stress, confirming that the generated shear
stress falls within the desired magnitude of 0.045 to 1.218 Pa.
Thus, the system is capable of effectively producing the
necessary fluid shear stress for chondrocyte studies.