BioAFM: Integrated atomic force and light microscopy for mechanochemical cell biology

We explore the environment surrounding us through the combination of multiple senses, i.e., sight, hearing, smell, taste, and touch. Sensing with light is very powerful as it allows us to detect objects without direct contact. However, there are types of information that can't be obtained by sight alone.

For example, touch tells us the mechanical properties of an object. By touching someone's hand with your finger, you can feel the texture of the skin and how soft or hard the skin is. You can also find how many fingers exist on that hand and even the bones beneath the skin and flesh.

Life science at the scale of molecular machinery, cells and tissues has been heavily relying on light microscopy especially when we try to observe them in their living state. Measurement of the mechanical properties by 'touching' should add another dimension to our sensing of the biological object and provides information that can't be obtained by light microscopy. An atomic force microscope (AFM) is an instrument that achieves such measurements.

We integrate an AFM with a light microscope that has two different modes of observation, 1) total internal fluorescence microscopy (TIRFM), which can detect single molecules by fluorescence, and 2) high-resolution 3D fluorescence microscopy (3DFM), which is suitable for observation of thick samples such as cell and tissues. The combination of AFM and TIRFM will allow us to visualize the live dynamics of the assembly of biomolecular machines that play key roles in the transport/traffic inside the cell.

AFM+3DFM enables us to measure various mechanical properties of a single cell of interest in a complex multicellular environment by using a fluorescent marker as a guide.

Our proposed and future BioAFM experiments will give new insights into cellular and molecular mechanisms of cell and tissue morphogenesis and other biological processes, in which mechanical force plays a key role.