A combined optical and atomic force microscope for live cell investigations

Area of Science:

• Biophysics
• Cell Biology
• Microscopy

Background:

• Live cell imaging requires techniques that preserve physiological conditions.
• Simultaneous acquisition of structural and functional data is crucial for understanding cellular dynamics.
• Atomic Force Microscopy (AFM) provides high-resolution topographical data, while fluorescence microscopy visualizes molecular components.

Purpose of the Study:

• To present an integrated atomic force microscope (AFM) and epi-fluorescence microscope system.
• To enable simultaneous live cell imaging under physiological conditions.
• To correlate cellular structure with molecular function.

Main Methods:

• Combining AFM with epi-fluorescence microscopy for simultaneous imaging.
• Utilizing differential interference contrast (DIC) for high-contrast optical imaging.
• Employing force spectroscopy with antibody-functionalized AFM tips to probe receptor clusters.

Main Results:

• High-resolution AFM images were acquired concurrently with fluorescence or DIC images.
• Synergistic effects between fluorescence imaging and AFM were demonstrated.
• Significantly higher binding probability was observed on fluorescence-identified receptor-positive sites compared to receptor-negative sites.

Conclusions:

• The integrated AFM-fluorescence microscope system facilitates simultaneous live cell imaging.
• This combined approach provides valuable correlations between cellular structure and molecular function.
• The system is effective for probing molecular interactions, such as receptor-ligand binding, at the nanoscale.