Wide-area scanner for high-speed atomic force microscopy

• Published in: Review of scientific instruments Vol. 84; no. 5; p. 053702
• Main Authors: Watanabe, Hiroki, Uchihashi, Takayuki, Kobashi, Toshihide, Shibata, Mikihiro, Nishiyama, Jun, Yasuda, Ryohei, Ando, Toshio
• Format: Journal Article
• Language: English
• Published: United States 01.05.2013
• Subjects: Actins - metabolism; Bacillus subtilis - cytology; Bacteriolysis; Endocytosis; HeLa Cells; Humans; Microscopy, Atomic Force - instrumentation; Muramidase - metabolism
• ISSN: 1089-7623
• DOI: 10.1063/1.4803449

High-speed atomic force microscopy (HS-AFM) has recently been established. The dynamic processes and structural dynamics of protein molecules in action have been successfully visualized using HS-AFM. However, its maximum scan ranges in the X- and Y-directions have been limited to ~1 μm and ~4 μm, respectively, making it infeasible to observe the dynamics of much larger samples, including live cells. Here, we develop a wide-area scanner with a maximum XY scan range of ~46 × 46 μm(2) by magnifying the displacements of stack piezoelectric actuators using a leverage mechanism. Mechanical vibrations produced by fast displacement of the X-scanner are suppressed by a combination of feed-forward inverse compensation and the use of triangular scan signals with rounded vertices. As a result, the scan speed in the X-direction reaches 6.3 mm/s even for a scan size as large as ~40 μm. The nonlinearity of the X- and Y-piezoelectric actuators' displacements that arises from their hysteresis is eliminated by polynomial-approximation-based open-loop control. The interference between the X- and Y-scanners is also eliminated by the same technique. The usefulness of this wide-area scanner is demonstrated by video imaging of dynamic processes in live bacterial and eukaryotic cells.