Ameboid cell migration through regular arrays of micropillars under confinement

Area of Science:

• Cell biology
• Biophysics
• Microfluidics

Background:

• Cell migration is crucial for physiological processes like immune response.
• Understanding how topography and crowding affect cell dynamics is essential.

Purpose of the Study:

• To investigate the impact of geometrical cues on the ameboid migration of HL-60 cells (neutrophils).
• To analyze cell behavior in confined geometries with varying pillar arrangements.

Main Methods:

• Utilized a microfluidic device to track HL-60 cell migration between parallel plates with micropillars.
• Varied vertical confinement (h) and pillar spacing (e) to observe cellular responses.
• Employed numerical simulations to disentangle the effects of cell-pillar contacts and trapping on diffusion.

Main Results:

• Cell contact time with pillars was independent of confinement (h) and spacing (e).
• Decreasing vertical confinement (h) reduced cell direction persistence but not velocity.
• Reducing pillar spacing (e) increased cell trapping and contact frequency, decreasing the diffusion constant (D).
• Simulations confirmed that cell-pillar contacts significantly impact diffusivity, especially at smaller pillar spacings.

Conclusions:

• Cell migration is adaptable to confinement, maintaining velocity under pressure but sacrificing directional control.
• Topographic features like micropillars create traps that hinder cell movement and reduce diffusion.
• The study provides insights into how physical microenvironments regulate cell migration, relevant for immune response and tissue engineering.