Cell motility regulation on a stepped micro pillar array device (SMPAD) with a discrete stiffness gradient

Area of Science:

• Biophysics
• Cell Biology
• Materials Science

Background:

• Cellular behavior is influenced by the mechanical properties of the surrounding tissue environment.
• Understanding mechanically driven cell migration requires precise control over substrate stiffness gradients.

Purpose of the Study:

• To develop a microfabricated platform that decouples substrate stiffness gradients from extracellular matrix (ECM) protein area.
• To investigate the effects of controlled mechanical stimuli on cell migration and behavior.

Main Methods:

• Fabrication of a "stepped" micro pillar array device (SMPAD) using double-step SU-8 mold technology.
• Modulation of substrate rigidity by altering pillar body diameter while maintaining constant cell contact area.
• Culturing C2C12, HeLa, and NIH3T3 cells on the SMPAD and observing their motion via time-lapse microscopy.

Main Results:

• Demonstrated directed cell migration guided by a discrete rigidity gradient.
• Observed that various cell types exhibit altered behavior in response to mechanical stimuli.
• Found that cell velocity was highest on substrates with the greatest stiffness.

Conclusions:

• The SMPAD provides a unique tool for studying cell migration and behavior in response to controlled mechanical environmental cues.
• This platform enables the regulation of mechanical properties independently of contact area effects.
• The findings highlight the significant impact of substrate stiffness on cell velocity and directed migration.