Engineering small tubes with changes in diameter for the study of kidney cell organization

Area of Science:

• Biomedical Engineering
• Cell Biology
• Microfluidics

Background:

• Multicellular tubes are vital for organ function, and their topology influences health and disease.
• Micrometric tubes, like those in the vascular or renal systems, subject cells to curvature, confinement, and flow.
• Changes in tube diameter create gradients in shear stress and curvature, potentially causing pathologies.

Purpose of the Study:

• To present a novel method for fabricating microfluidic devices with biomimetic tube geometries.
• To create a platform for investigating cellular responses to mechanical stimuli in physiologically relevant tube structures.
• To replicate renal tubule environments on-chip for detailed cellular analysis.

Main Methods:

• Microfabrication using molded etched tungsten wires to create polydimethylsiloxane (PDMS) microdevices.
• Integration of cylindrical channels with controlled changes in diameter (80 μm to 50 μm).
• Seeding and culturing of renal cell lines within the biomimetic microfluidic tubes.

Main Results:

• Successful creation of a microfluidic device mimicking in vivo tube geometries, including diameter transitions.
• Demonstration of renal tubule replication on-chip, enabling cell culture in curved, confined spaces.
• Investigation of cell morphology and orientation in response to tube curvature and shear stress gradients.

Conclusions:

• The developed microfluidic platform effectively mimics biological tubes, facilitating the study of mechanotransduction.
• This technology allows for simultaneous assessment of cellular responses to differential mechanical constraints in interconnected tube segments.
• The system provides a valuable tool for understanding the role of mechanical forces in organ function and the development of obstructive or cystic diseases.