Fabrication of a circular PDMS microchannel for constructing a three-dimensional endothelial cell layer

Area of Science:

• Microfluidics
• Biomaterials Engineering
• Cell Biology

Background:

• Microfluidic devices are crucial for mimicking in vivo environments.
• Fabricating circular microchannels presents fabrication challenges.
• Existing methods lack simplicity and efficiency for circular channel generation.

Purpose of the Study:

• To develop a straightforward and efficient method for fabricating circular microfluidic channels.
• To utilize the reflow phenomenon of positive photoresist for channel fabrication.
• To demonstrate the utility of these channels for endothelial cell culture.

Main Methods:

• Fabrication of rectangular photoresist micropatterns on silicon wafers via photolithography.
• Conversion of rectangular patterns to half-circular shapes using controlled thermal reflow (~105 °C).
• Replication of the photoresist template using polydimethylsiloxane (PDMS) and bonding to form circular channels.

Main Results:

• Achieved tunable circular microchannels with diameters ranging from 100 to 400 μm.
• Successfully fabricated various channel geometries (straight, S-curve, X-, Y-, T-shapes).
• Demonstrated successful culture of human umbilical vein endothelial cells within the circular PDMS microchannels, showing adhesion, proliferation, and alignment.

Conclusions:

• The reflow method offers a simple and efficient approach for creating circular microfluidic channels.
• The fabricated channels effectively support endothelial cell growth and organization, mimicking vascular networks.
• This technique provides a versatile platform for advanced microfluidic cell culture applications.