Standardized Nanomechanical Atomic Force Microscopy Procedure (SNAP) for Measuring Soft and Biological Samples.

Area of Science:

• Biophysics
• Materials Science
• Cell Biology

Background:

• Atomic Force Microscopy (AFM) is crucial for nanomechanical characterization.
• Accurate determination of elastic modulus in soft samples, like living cells, is challenging due to measurement variability.
• Existing AFM force spectroscopy methods require precise optical lever system adjustment for reliable data.

Purpose of the Study:

• To develop a standardized procedure for reliable elastic modulus determination using AFM.
• To minimize instrument, laboratory, and operator-dependent errors in AFM measurements.
• To validate the procedure's effectiveness across different labs and sample types.

Main Methods:

• Introduced the Standardized Nanomechanical AFM Procedure (SNAP).
• Ensured precise AFM optical lever system adjustment.
• Calculated deflection sensitivity using vibrometer-determined spring constants to eliminate errors.

Main Results:

• Reduced variability in hydrogel elastic moduli measurements to 1%.
• Increased consistency in living cells elasticity measurements by a factor of two.
• Validated the procedure across a network of European laboratories.

Conclusions:

• SNAP provides highly reproducible elasticity measurements for soft samples and living cells.
• Improved consistency enhances the applicability of cell mechanics as a quantitative diagnostic marker.
• The procedure ensures reliable, instrument-independent nanomechanical measurements.