A stretching device for high-resolution live-cell imaging

Area of Science:

• Cell Biology
• Biophysics
• Bioengineering

Background:

• Investigating cellular responses to substrate strain is crucial for understanding mechanobiology.
• Existing devices often limit high-resolution live-cell imaging during mechanical stretching.
• Real-time analysis of structural dynamics in living cells under strain remains a challenge.

Purpose of the Study:

• To introduce a novel stretch device optimized for high-resolution live-cell imaging.
• To enable detailed analysis of cellular structural remodeling under controlled mechanical strain.
• To investigate the transmission and focusing of mechanical stress within cellular structures.

Main Methods:

• Developed a novel stretch device compatible with inverted microscopes for live-cell imaging.
• Applied constant magnitude or cyclic stretch at physiological levels to cells on elastic membranes.
• Utilized interchangeable indenters for equibiaxial and uniaxial stretch profiles.
• Tracked fluorescent microspheres to analyze strain profiles and quantified cellular responses using microscopy.

Main Results:

• The device reproducibly applied defined stretch profiles (equibiaxial and uniaxial).
• Mechanical strain efficiently transmitted through the extracellular matrix and focal adhesions to endothelial cells.
• Reduced strain transmission to the intermediate filament network (vimentin) was observed, with strain focusing at discrete sites.
• Actin-mediated edge ruffling showed no desensitization to repeated mechanostimulation.

Conclusions:

• The novel stretch device is a valuable tool for live-cell microscopy of mechanical strain effects.
• It facilitates the measurement of dynamic structural remodeling in response to mechanical stimuli.
• The findings provide new insights into how cells perceive and respond to mechanical forces at the structural level.