Modulating wall shear stress gradient via equilateral triangular channel for in situ cellular adhesion assay

Area of Science:

• Microfluidics
• Biophysics
• Cell Biology

Background:

• Cell adhesion is crucial for biological processes.
• Quantifying cell adhesion strength requires precise control over forces.
• Existing microfluidic methods for cell adhesion assays have limitations in WSS gradient control.

Purpose of the Study:

• To introduce a novel microfluidic channel, the equilateral triangular channel (ETRIC), for cell adhesion assays.
• To enable precise modulation and generation of wall shear stress (WSS) gradients.
• To facilitate real-time screening of cell detachment and measurement of adhesion strength.

Main Methods:

• Design and fabrication of an equilateral triangular channel (ETRIC).
• Derivation of an exact analytical solution for the velocity field.
• Validation of the analytical solution using numerical simulations and particle image velocimetry (PIV).
• Generation and modulation of a parabolic WSS gradient by adjusting flow rate.

Main Results:

• The ETRIC generates a stable, symmetric parabolic WSS gradient perpendicular to the flow.
• An exact analytical solution for the velocity field simplifies WSS modulation.
• The channel allows for real-time, in situ screening of cell detachment under defined WSS gradients.
• WSS gradients from 0 to 160 dyn/cm² were achieved, enabling adhesion strength measurement and time-dependent detachment studies of NIH-3T3 cells.

Conclusions:

• The ETRIC is a versatile microfluidic tool for cell adhesion studies.
• Its unique geometry and analytical solution facilitate precise control and efficient experimentation.
• The device enables comprehensive investigation of cell adhesion dynamics and strength.