<Overview of each Bio-SPM technology>
Atomic resolution/3D-AFM (FM-AFM)
FM-AFM （Frequency-modulation Atomic Force Microscope）can visualize
subnanometer-scale surface structures of biomolecules in solution. Combinedwith 3D scanning technique, it can also visualize 3D distribution of hydrationand flexible surface structures at solid-liquid interfaces. The imaging rate of FMAFM and 3D-AFM is typically 1 min/frame. The optimal spatial resolution of theinstrument is 0.3 nm in the lateral direction and 0.01 nm in the vertical direction.
In the case of biomolecular imaging, the practical resolution is mostly
determined by the fluctuation of the surface structures rather than theinstruments. For more details, see the following articles:
1. H. Asakawa, S. Yoshioka, K. Nishimura, T. Fukuma, “Spatial Distributionof Lipid Headgroups and Water Molecules at Membrane/Water Interfaces
Visualized by Three-Dimensional Scanning Force Microscopy”, ACS
Nano 6, 9013-9020 (2012).
2. H. Asakawa, K. Ikegami, M. Setou, N. Watanabe, M. Tsukada, T.
Fukuma, “Submolecular-Scale Imaging of α-Helices and C-TerminalDomains of Tubulins by Frequency Modulation Atomic Force Microscopy
in Liquid”, Biophys. J. 101, 1270-1276 (2011).
3. T. Fukuma, “Water distribution at solid/liquid interfaces visualized byfrequency modulation atomic force microscopy”, Sci. Technol. Adv.
Mater. 11, 033003 (18 pages) (2010).
High-speed AFM (HS-AFM)
HS-AFM (High-speed Atomic Force Microscope) can visualize moving objects
in solution. Its temporal resolution is typically 100 ms/frame, while the spatialresolution is 2-3 nm in the lateral direction and 0.15 nm in the vertical direction.
When it is applied to protein molecules in action, the acquired HS-AFM images
can provide a significant insight into how the molecules function. For moredetails, see the following review articles:1. T. Ando, T. Uchihashi, S. Scheuring, "Filming biomolecular processes byhigh-speed atomic force microscopy", Chem. Rev. 114, 3120-3188(2014).
2. T. Ando, T. Uchihashi, N. Kodera, "High-speed AFM and applications tobiomolecular systems", Annu. Rev. Biophys. 42, 393-414 (2013).
3. T. Uchihashi, N. Kodera, T. Ando, "Guide to video recording of structure
dynamics and dynamic processes of proteins by high-speed atomic force
microscopy", Nature Protocols 7, 1193-1206 (2012).
Scanning Ion Conductance Microscopy (SICM)
SICM has a unique measurement principle and provides unprecedented
opportunity that enables submicroscale functional imaging of single live cells by
a combination of nanoscale local stimulation and noncontact topography
imaging. The imaging rate of SICM is 30-300 s/frame. Spatial resolution of theinstrument is 10 nm in the lateral direction and 5 nm in the vertical direction. For
more details, see the following articles:
1. P. Novak, C. Li, A. I. Shevchuk, R. Stepanyan, M. Caldwell, S. Hughes,
T. G. Smart, J. Gorelik, V. P. Ostanin, M. J. Lab, G. W. J. Moss, G. I.
Frolenkov, D. Klenerman, and Y. E. Korchev, “Nanoscale live-cell
imaging using hopping probe ion conductance microscopy”, Nat.
Methods 6, 279-281 (2009).
2. V. O. Nikolaev, A. Moshkov, A. R. Lyon, M. Miragoli, P. Novak, H. Paur,
M. J. Lohse, Y. E. Korchev, S. E. Harding, and J. Gorelik, “beta(2)Adrenergic Receptor Redistribution in Heart Failure Changes cAMP
Compartmentation”, Science 327, 1653-1657 (2010).
3. Zhou, M. Saito, T. Miyamoto, P. Novak, A. Shevchuk, Y. Korchev, T.
Fukuma, Y. Takahashi, “Nanoscale Imaging of Primary Cilia withScanning Ion Conductance Microscopy,” Anal. Chem. 90, 2891-2895(2018).
AFM for Cell Measurement
Based on high-speed AFM or 3D-AFM, NanoLSI is developing AFM
technologies for measuring the structure, dynamics or mechanical properties ofthe surface or inside of cells at a nano scale. High-speed AFM successfullyvisualized the surface structure of bacteria at a molecular scale and nanomotion of the terminal portion of nerve cells. Based on 3D-AFM, we developed
a nanoendoscopy-AFM technique. Using this technique, we succeeded in threedimensional observation of cell nucleus or actin fibers inside live cells, themeasurement of two-dimensional nanodynamics of inner scaffold of plasma
membrane, and the measurement of the surface stiffness of cell nucleus. For
more details, see the following articles:
1. H. Yamashita, A. Taoka; T. Uchihashi, T. Asano, T. Ando, Y. Fukumori,“Single-molecule imaging on living bacterial cell surface by high-speed
AFM”, J. Mol. Biol. 422 (2), 300-9 (2012).
2. M. Shibata, T. Uchihashi, T. Ando, R. Yasuda, “Long-tip high-speed
atomic force microscopy for nanometer-scale imaging in live cells”, Sci.
Rep., 5, 8724 (2015).
3. M. Penedo, K. Miyazawa, N. Okano, Furusho, H. Ichikawa, T, S. AlamMohammad, K. Miyata, C. Nakamura, T. Fukuma, “Visualizing
intracellular nanostructures of living cells by nanoendoscopy-AFM”, Sci.
Adv. 7 (52), eabj4990 (2021).
4. K. Kobayashi, N. Kodera, T. Kasai, YO. Tahara, T. Toyonaga, M.
Mizutani, I. Fujiwara, T. Ando, M. Miyata. “Movements of Mycoplasma
mobile gliding machinery detected by high-speed atomic force
microscopy”, mBio 12: e00040-21 (2021).