Simple haptotactic gradient generation within a triangular microfluidic channel.

Area of Science:

• Biomedical Engineering
• Cell Biology
• Microfluidics

Background:

• Current microfluidic devices for live cell analysis often use simple channel shapes, relying on complex networks for fluidic control.
• Generating spatial gradients of bioactive ligands typically requires intricate device geometries.

Purpose of the Study:

• To present a straightforward method for creating defined and predictable surface-bound molecule gradients.
• To demonstrate the utility of triangular cross-section channels for generating flow velocity variations and subsequent molecule deposition.

Main Methods:

• Fabrication of microfluidic channels with triangular cross-sections using bulk wet etching and polydimethylsiloxane (PDMS) replica molding.
• Analytical modeling and simulation to predict solute deposition based on flow rates.
• Experimental validation using flow rate visualization and deposition of fibronectin-rhodamine.

Main Results:

• A method was developed to generate predictable gradients of surface-bound molecules within triangular microchannels.
• Flow rate variations within the triangular channel were shown to control solute deposition across the channel width.
• The generated fibronectin gradient successfully induced robust haptotaxis in Chinese Hamster Ovary (CHO) cells.

Conclusions:

• Triangular microchannels offer a simple yet effective platform for generating precise molecular gradients.
• This approach simplifies microfluidic device design, facilitating the incorporation of additional functional features.
• The method shows promise for advanced cell migration studies and lab-on-a-chip applications.