Topography of Cells Revealed by Variable-Angle Total Internal Reflection Fluorescence Microscopy.

Area of Science:

• Biophysics
• Cell Biology
• Microscopy

Background:

• Total Internal Reflection Fluorescence (TIRF) microscopy is a powerful technique for studying cell-surface interactions.
• Existing TIRF methods have limitations in precisely quantifying cell membrane topography and adhesion dynamics.
• Advancements in microscopy are crucial for understanding complex cellular processes.

Purpose of the Study:

• To introduce an improved variable-angle total internal reflection fluorescence microscopy (vaTIRFM) technique.
• To develop a theoretical framework and image processing method for accurate membrane/substrate separation distance measurement.
• To demonstrate the utility of vaTIRFM in quantifying the adhesion of motile cancer cells.

Main Methods:

• Acquisition of a stack of TIRF images by systematically varying the incident light angle.
• Development of a comprehensive theoretical model to extract membrane/substrate separation distances.
• Implementation of straightforward image processing algorithms for topographic mapping.

Main Results:

• Achieved nanometric axial resolution (typically 10-20 nm) in topographic measurements.
• Successfully quantified the adhesion process of MDA-MB-231 cancer cells on fibronectin-coated glass.
• Demonstrated the capability of vaTIRFM to reveal new insights into cell adhesion dynamics.

Conclusions:

• The improved vaTIRFM offers enhanced capabilities for high-resolution cell topography mapping.
• This technique provides a valuable tool for quantifying dynamic cell adhesion processes.
• vaTIRFM opens new avenues for investigating cell mechanics and behavior at the nanoscale.