Fibroblast migration correlates with matrix softness. A study in knob-hole engineered fibrin

Area of Science:

• Biomaterials Science
• Cell Biology
• Biophysics

Background:

• Cell invasion into extracellular matrices is crucial for tissue remodeling.
• In 2D models, cells exhibit durotaxis, preferring stiffer environments.
• The impact of matrix mechanics on 3D cell migration remains less understood.

Purpose of the Study:

• To investigate how matrix mechanical properties influence 3D cell migration rates.
• To determine if 3D cell migration follows durotaxis principles observed in 2D.
• To develop methods for controlling cell invasion speed through matrix modification.

Main Methods:

• Fabrication of tunable fibrin-based hydrogels functionalized with poly(ethylene glycol) (PEG).
• Varied gel stiffness by introducing defects in fibrin fibers, preserving nanostructure.
• Quantified cell migration rates in 3D matrices of differing stiffness using fibroblast invasion assays.

Main Results:

• 3D cell migration rate was inversely correlated with matrix stiffness; softer matrices facilitated faster invasion.
• Matrix softening was achieved by introducing defects via PEGylation, without altering network architecture.
• Fibroblast migration speed was primarily determined by the elastic modulus, not PEG content or identity.

Conclusions:

• Unlike 2D durotaxis, 3D cell migration speed is enhanced in softer matrices.
• Matrix stiffness, modulated by fiber defects, is a key regulator of 3D cell invasion.
• This study offers a strategy to fine-tune cell colonization speed by controlling matrix mechanics.