Mapping nanomechanical properties of live cells using multi-harmonic atomic force microscopy.

Area of Science:

• Cellular and Molecular Biophysics
• Nanotechnology
• Biomaterials Science

Background:

• Nanomechanical properties like elasticity and adhesion are crucial for cellular functions.
• Existing quasi-static atomic force microscopy (AFM) methods lack the necessary spatial and temporal resolution for detailed cellular analysis.

Purpose of the Study:

• To develop a high-throughput dynamic AFM method for quantitative mapping of live cell nanomechanical properties.
• To overcome the resolution limitations of conventional AFM techniques for studying dynamic cellular processes.

Main Methods:

• Utilized dynamic atomic force microscopy (AFM) to measure cellular nanomechanics.
• Analyzed the 0th, 1st, and 2nd harmonic components of the AFM cantilever's Fourier spectrum during interaction with cell surfaces.
• Mapped local stiffness, stiffness gradient, and viscoelastic dissipation.

Main Results:

• Achieved a throughput 10-1,000 times higher than quasi-static AFM.
• Successfully mapped nanomechanical properties of live Escherichia coli bacteria, rat fibroblasts, and human red blood cells.
• Demonstrated sub-10 nm detail in mechanical property mapping.

Conclusions:

• The developed dynamic AFM method provides a quantitative and high-throughput approach to map live cell nanomechanics.
• This technique is compatible with commercial AFM systems and has potential applications in studying tumors, cells, and biofilms.