Measuring the mechanical properties of living cells using atomic force microscopy

Area of Science:

• Biophysics
• Cell Biology
• Materials Science

Background:

• Cellular and extracellular matrix (ECM) mechanical properties are vital for biological processes like stem cell differentiation and tumor formation.
• Changes in cell and ECM stiffness can indicate altered cell physiology or tissue diseases, making cell stiffness a key indicator of cell culture status.
• Micro-indentation using Atomic Force Microscope (AFM) is a reliable method for measuring the stiffness of living cells and tissues.

Purpose of the Study:

• To demonstrate the procedure for characterizing the stiffness of living cells using AFM.
• To provide a detailed guide on AFM calibration, force-curve acquisition, and data analysis for cell stiffness measurements.
• To highlight the capabilities and limitations of AFM-based micro-indentation for biological applications.

Main Methods:

• Utilizing Atomic Force Microscope (AFM) for micro-indentation of living cells.
• Applying Hertz model to force-indentation curves for quantitative stiffness measurements.
• Employing a MATLAB routine for data analysis, including AFM calibration and force-curve acquisition.

Main Results:

• Successfully demonstrated the quantitative measurement of living cell stiffness using AFM micro-indentation.
• Detailed the critical steps involved in AFM calibration and force-curve acquisition for accurate results.
• Presented a data analysis workflow using MATLAB for interpreting force-indentation data.

Conclusions:

• AFM micro-indentation is an effective method for assessing living cell mechanical properties.
• Accurate calibration and data analysis are essential for reliable cell stiffness measurements.
• Understanding cell stiffness through AFM provides insights into cell physiology and disease states.