Control techniques in high-speed atomic force microscopy

Abstract

Abstract-Biological macromolecules are highly dynamic. Their functions results from dynamic structural changes and dynamic interactions with other molecules. The visualization of the dynamic processes at high spatial and temporal resolution appears to be straightforward to understanding the functional mechanisms of biological macromolecules. Such visualization is only possible by the atomic force microscope (AFM) with a high-speed imaging capability, since dynamic biomolecular processes generally occur on a millisecond timescale. Therefore, we have been improving both the scan speed as well as the tip force exerted on the sample by developing various devises and techniques. The latest version of our high-speed AFM can capture biological processes at an imaging rate of 30-100 ms/frame without disturbing their functions. Here, we report the devices and techniques that realized this performance.

Data-Driven Controller Design for Atomic-Force Microscopy

“…The superimposed structural resonances of piezo-actuator-based scanners for AFM make high-speed control challenging. Several model-based approaches have been presented over the years in Schitter et al (2003);Fantner et al (2006);Ando (2008). However, in practice the use of parametric models has significant disadvantages.…”

Ultra-high speed atomic force microscopy: Video-rate and beyond

“…T Atomic Force Microscopy (AFM) systems [1][2][3] have revolutionized nanoscience and engineering with impact on biology and material sciences [1][2][3][4][5]. These fundamental tools are enabling discoveries in material behavior, bonding, and evaluation as well as cell and cell-membrane diagnosis through imaging and manipulation [1].…”

“…These fundamental tools are enabling discoveries in material behavior, bonding, and evaluation as well as cell and cell-membrane diagnosis through imaging and manipulation [1]. Yet, present AFM systems have challenging limitations characterized by specific features that this paper identifies and seeks to eliminate [1][2][3][4][5]. A compelling challenge in High speed AFM in aqueous solutions is to be able to visualize (biological) proteins in action--without disturbing their functioning.…”

“…A compelling challenge in High speed AFM in aqueous solutions is to be able to visualize (biological) proteins in action--without disturbing their functioning. In liquid solutions, the cantilever Q-factor is extremely reduced due to hydrodynamic interactions between the cantilever and the liquid thus hindering imaging (see [1][2][3]). …”

Real‐Time Sliding Mode Observer Scheme for Shear Force Estimation in a Transverse Dynamic Force Microscope

“…The bending of the cantilever, when obtained at different positions as part of a raster scan of the sample surface, creates a high resolution topographical image. Significant advances have been made in terms of achieving higher temporal resolution through improved electronics in conjunction with sophisticated control approaches [1][2][3][4], stable fast-scan sample stages [5], and by miniaturising cantilevers [6]. In particular, the miniaturisation of cantilevers increases their resonance frequency, and thus increases the bandwidth of the detection system [7].…”