Force and Compliance Measurements on Living Cells Using Atomic Force Microscopy (AFM)

Area of Science:

• Biophysics
• Cell Biology
• Materials Science

Background:

• Cell adhesion is crucial for biological processes.
• Understanding cell mechanics and molecular interactions is vital.
• Leukocyte function-associated antigen-1 (LFA-1) and intercellular adhesion molecule-1 (ICAM-1) mediate cell adhesion.

Purpose of the Study:

• To utilize atomic force microscopy (AFM) for quantifying single LFA-1/ICAM-1 bond dynamics.
• To investigate cell compliance and mechanical properties using AFM.
• To elucidate the mechanism of cell adhesion through force measurements.

Main Methods:

• Atomic Force Microscopy (AFM) was employed as a force spectroscopy tool.
• Single-bond force measurements of LFA-1/ICAM-1 interactions at varying loading rates.
• AFM was used as a microindenter to assess cell mechanical properties.
• Multiple-bond force measurements were conducted to understand adhesion mechanisms.

Main Results:

• The dynamic strength of single LFA-1/ICAM-1 bonds was determined.
• The activation potential overcome during LFA-1/ICAM-1 complex breakage was characterized.
• Cellular mechanical properties (compliance) were quantified.
• Insights into the mechanism of cell adhesion were gained from multi-bond force data.

Conclusions:

• AFM is a powerful tool for dissecting molecular interactions in cell adhesion.
• Quantitative analysis of single-molecule forces provides critical data on receptor-ligand dynamics.
• AFM-based microindentation offers a method for characterizing cell mechanical properties.
• The study provides a foundation for understanding cell adhesion in various biological contexts.