Fibroblast adaptation and stiffness matching to soft elastic substrates

Area of Science:

• Biophysics
• Cell Biology
• Materials Science

Background:

• Cells alter morphology and gene expression based on substrate rigidity.
• Cellular internal stiffness is influenced by the cytoskeleton and internal stresses.

Purpose of the Study:

• To investigate how fibroblast internal stiffness changes in response to substrate stiffness.
• To explore the relationship between substrate rigidity and cellular mechanical properties.

Main Methods:

• Atomic force microscopy was employed to measure fibroblast stiffness.
• Cells were cultured on fibronectin-coated polyacrylamide gels with varying shear moduli (500–40,000 Pa).

Main Results:

• Cellular elastic moduli matched or were slightly lower than substrate moduli for soft gels.
• Fibroblast stiffness saturated at substrate rigidities around 20 kPa.
• Increased substrate stiffness correlated with higher levels of cross-linked F-actin.

Conclusions:

• Fibroblasts actively tune their internal stiffness to match substrate rigidity within the range of soft tissues.
• Environmental rigidity modulation of cellular stiffness is a potential mechanism for directing cell migration and wound repair.