Nanoscale Wetting of Single Viruses

The epidemic spread of many viral infections is mediated by the environmental conditions and influenced by the ambient humidity. Single virus particles have been mainly visualized by atomic force microscopy (AFM) in liquid conditions, where the effect of the relative humidity on virus topography and surface cannot be systematically assessed. In this work, we employed multi-frequency AFM, simultaneously with standard topography imaging, to study the nanoscale wetting of individual Tobacco Mosaic virions (TMV) from ambient relative humidity to water condensation (RH > 100%). We recorded amplitude and phase vs. distance curves (APD curves) on top of single virions at various RH and converted them into force vs. distance curves. The high sensitivity of multifrequency AFM to visualize condensed water and sub-micrometer droplets, filling gaps between individual TMV particles at RH > 100%, is demonstrated. Dynamic force spectroscopy allows detecting a thin water layer of thickness ⁓1 nm, adsorbed on the outer surface of single TMV particles at RH < 60%.

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Enhanced Capacitive Humidity Sensing Performance at Room Temperature via Hydrogen Bonding of Cyanopyridone-Based Oligothiophene Donor

Chemosensors ◽

10.3390/chemosensors9110320 ◽

2021 ◽

Vol 9 (11) ◽

pp. 320

Author(s):

Salman Ali ◽

Mohammed A. Jameel ◽

Christopher J. Harrison ◽

Akhil Gupta ◽

Richard A. Evans ◽

...

Keyword(s):

Hydrogen Bonding ◽

Relative Humidity ◽

Room Temperature ◽

High Sensitivity ◽

Vital Role ◽

Humidity Sensing ◽

Force Microscopy ◽

Long Term Stability ◽

Atomic Force ◽

Sensing Performance

Cyanopyridone-based oligothiophene donors with both hydrophobic and hydrophilic characters have been evaluated as active layers within simple capacitive devices for humidity sensing at room temperature. Surface studies using atomic force microscopy revealed a self-assembled nanofibrous network with a thin needle-like structure for the terminal hydroxy example (CP6), devoid in the methyl example (CP1). The sensing performance of each sensor was investigated over a broad range of relative humidity levels as a function of capacitance at room temperature. The sensor CP6 demonstrated favourable features such as high sensitivity (12.2 pF/%RH), quick response/recovery (13 s/20.7 s), wide working range of relative humidity (10%–95% RH), low hysteresis (0.57%), outstanding recyclability, and excellent long-term stability. From the results obtained, hydrophilicity and hydrogen bonding appear to play a vital role in enhancing humidity sensing performance, leading to possible new design directions for simple organic semiconductor-based sensors.

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Experimental amplitude and frequency control of a self-excited microcantilever by linear and nonlinear feedback

Journal of Micromechanics and Microengineering ◽

10.1088/1361-6439/ac4643 ◽

2021 ◽

Author(s):

Eisuke Higuchi ◽

Hiroshi Yabuno ◽

Yasuyuki Yamamoto ◽

Sohei Matsumoto

Keyword(s):

Steady State ◽

Frequency Control ◽

High Sensitivity ◽

High Viscosity ◽

Measurement Methods ◽

Nonlinear Feedback ◽

Force Microscopy ◽

Atomic Force ◽

Excited Oscillation ◽

Experimental Approaches

Abstract In recent years, measurement methods that use resonators as microcantilevers have attracted attention because of their high sensitivity, high accuracy, and rapid response time. They have been widely utilized in mass sensing, stiffness sensing, and atomic force microscopy (AFM), among other applications. In all these methods, it is essential to accurately detect shifts in the natural frequency of the resonator caused by an external force from a measured object or sample. Experimental approaches based on self-excited oscillation enable the detection of these shifts even when the resonator is immersed in a high-viscosity environment. In the present study, we experimentally and theoretically investigate the nonlinear characteristics of a microcantilever resonator and their control by nonlinear feedback. We show that the steady-state response amplitude and the corresponding response frequency can be controlled by cubic nonlinear velocity feedback and cubic nonlinear displacement feedback, respectively. Furthermore, the amplitude and frequency of the steady-state self-excited oscillation can be controlled separately. These results will expand application of measurement methods that use self-excited resonators.

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Atomic Force Microscopy

Introduction to Scanning Tunneling Microscopy ◽

10.1093/oso/9780198856559.003.0016 ◽

2021 ◽

pp. 379-400

Author(s):

C. Julian Chen

Keyword(s):

Atomic Force Microscopy ◽

Entire Range ◽

Tunneling Current ◽

Vibrational Amplitude ◽

Dynamic Mode ◽

Dynamic Force ◽

Force Detection ◽

Static Mode ◽

Force Microscopy ◽

Atomic Force

This chapter discusses atomic force microscopy (AFM), focusing on the methods for atomic force detection. Although the force detection always requires a cantilever, there are two types of modes: the static mode and the dynamic mode. The general design and the typical method of manufacturing of the cantilevers are discussed. Two popular methods of static force detection are presented. The popular dynamic-force detection method, the tapping mode is described, especially the methods in liquids. The non-contact AFM, which has achieved atomic resolution in the weak attractive force regime, is discussed in detail. An elementary and transparent analysis of the principles, including the frequency shift, the second harmonics, and the average tunneling current, is presented. It requires only Newton’s equation and Fourier analysis, and the final results are analyzed over the entire range of vibrational amplitude. The implementation is briefly discussed.

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Atomic force microscopy reveals how relative humidity impacts the Young’s modulus of lignocellulosic polymers and their adhesion with cellulose nanocrystals at the nanoscale

International Journal of Biological Macromolecules ◽

10.1016/j.ijbiomac.2019.10.074 ◽

2020 ◽

Vol 147 ◽

pp. 1064-1075 ◽

Cited By ~ 2

Author(s):

Carlos Marcuello ◽

Laurence Foulon ◽

Brigitte Chabbert ◽

Veronique Aguié-Béghin ◽

Michael Molinari

Keyword(s):

Atomic Force Microscopy ◽

Relative Humidity ◽

Young’S Modulus ◽

Cellulose Nanocrystals ◽

Young's Modulus ◽

Force Microscopy ◽

Atomic Force

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Recovery dynamics of acrylic coating surfaces under elevated relative humidity monitored by atomic force microscopy

Progress in Organic Coatings ◽

10.1016/j.porgcoat.2020.105712 ◽

2020 ◽

Vol 146 ◽

pp. 105712

Author(s):

Qi Chen ◽

Mingwen Tian ◽

Kristel de Vos ◽

Maud Kastelijn ◽

Ron A.H. Peters ◽

...

Keyword(s):

Atomic Force Microscopy ◽

Relative Humidity ◽

Force Microscopy ◽

Acrylic Coating ◽

Atomic Force ◽

Recovery Dynamics

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Dynamic-force spectroscopy measurement with precise force control using atomic-force microscopy probe

Journal of Applied Physics ◽

10.1063/1.2355432 ◽

2006 ◽

Vol 100 (7) ◽

pp. 074315 ◽

Cited By ~ 16

Author(s):

Osamu Takeuchi ◽

Takaaki Miyakoshi ◽

Atsushi Taninaka ◽

Katsunori Tanaka ◽

Daichi Cho ◽

...

Keyword(s):

Atomic Force Microscopy ◽

Force Control ◽

Force Spectroscopy ◽

Dynamic Force ◽

Atomic Force Microscopy Probe ◽

Dynamic Force Spectroscopy ◽

Force Microscopy ◽

Spectroscopy Measurement ◽

Atomic Force

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Environmental chamber with controlled temperature and relative humidity for ice crystallization kinetic measurements by atomic force microscopy

Review of Scientific Instruments ◽

10.1063/1.5132537 ◽

2020 ◽

Vol 91 (2) ◽

pp. 023704 ◽

Cited By ~ 1

Author(s):

Melisa M. Gianetti ◽

Julián Gelman Constantin ◽

Horacio R. Corti ◽

M. Paula Longinotti

Keyword(s):

Atomic Force Microscopy ◽

Relative Humidity ◽

Crystallization Kinetic ◽

Kinetic Measurements ◽

Environmental Chamber ◽

Force Microscopy ◽

Atomic Force ◽

Ice Crystallization

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Different directional energy dissipation of heterogeneous polymers in bimodal atomic force microscopy

RSC Advances ◽

10.1039/c9ra03995c ◽

2019 ◽

Vol 9 (47) ◽

pp. 27464-27474 ◽

Cited By ~ 2

Author(s):

Xinfeng Tan ◽

Dan Guo ◽

Jianbin Luo

Keyword(s):

Atomic Force Microscopy ◽

Energy Dissipation ◽

Dynamic Force ◽

Force Detection ◽

Force Microscopy ◽

Nanomechanical Properties ◽

Powerful Technique ◽

Atomic Force ◽

Nanoscale Imaging ◽

Heterogeneous Polymers

Dynamic force microscopy (DFM) has become a multifunctional and powerful technique for the study of the micro–nanoscale imaging and force detection, especially in the compositional and nanomechanical properties of polymers.

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