Mapping of adhesion forces on soil minerals in air and water by atomic force spectroscopy (AFS)

2003 ◽  
Vol 17 (16) ◽  
pp. 2141-2156 ◽  
Author(s):  
F. L. Leite ◽  
A. Riul ◽  
P. S. P. Herrmann
2005 ◽  
Vol 11 (S03) ◽  
pp. 130-133 ◽  
Author(s):  
F. L. Leite ◽  
E. C. Ziemath ◽  
O. N. Oliveira Jr. ◽  
P. S. P. Herrmann

The possibility of analyzing surfaces at the nanoscale provided by atomic force microscopy [1] (AFM) has been explored for various materials, including polymers [2], biological materials [3] and clays [4]. Further uses of AFMs involved nanomanipulation [5] and measurements of interaction forces, where the latter has been referred to as atomic force spectroscopy (AFS) [6]. Measurements of surface-surface interactions at the nanoscale are important because many materials have their properties changed at this range [7]. For samples in air, the interactions with the tip are a superimposition of van der Waals, electrostatic and capillary forces. A number of surface features can now be monitored with AFS, such as adsorption processes and contamination from the environment. Many implications exist for soil sciences and other areas, because quantitative knowledge of particle adhesion is vital for understanding technological processes, including particle aggregation in mineral processing, quality of ceramics and adhesives. In this paper, we employ AFS to measure adhesion (pull-off force) between the AFM tip and two types of substrate. Adhesion maps are used to illustrate sample regions that had been contaminated with organic compounds.


2012 ◽  
Vol 18 (5) ◽  
pp. 1088-1094 ◽  
Author(s):  
M. Papi ◽  
A. Maiorana ◽  
F. Bugli ◽  
R. Torelli ◽  
B. Posteraro ◽  
...  

AbstractAspergillus fumigatus has become a leading cause of fungal morbidity and mortality, especially in immunocompromised patients. This fungus is able to grow as a multicellular community and produce a hydrophobic extracellular matrix (ECM), mainly composed of galactomannan and α-1,3 glucans, to protect itself from host defenses and antimicrobial drugs. This matrix envelops the fungus hyphae, binding them into a contiguous sheath on the colony surface, forming a biofilm and increasing the fungal resistance to adverse environmental factors. Adherence to host cells and resistance to physical removal play a key role in fungal colonization and invasion of the host and in a wide range of infections. Here we show that, by using atomic force spectroscopy, it is possible to exploit the peculiar hydrophobicity of the biofilm components (i.e., cell walls, ECM) to detect the biofilm spread, its growth, and lysis on rough surfaces. By means of this approach, we demonstrate that alginate lyase, an enzyme known to reduce negatively charged alginate levels in microbial biofilms, reduces the biofilm adhesion forces suggesting a loss of ECM from the biofilm, which could be used to enhance pharmacological treatments.


Micron ◽  
2021 ◽  
Vol 145 ◽  
pp. 103062
Author(s):  
Agnieszka Maria Kolodziejczyk ◽  
Paulina Sokolowska ◽  
Aleksandra Zimon ◽  
Magdalena Grala ◽  
Marcin Rosowski ◽  
...  

2019 ◽  
Vol 2 (1) ◽  
Author(s):  
Carolina Pimenta-Lopes ◽  
Carmen Suay-Corredera ◽  
Diana Velázquez-Carreras ◽  
David Sánchez-Ortiz ◽  
Jorge Alegre-Cebollada

2015 ◽  
Vol 5 (2) ◽  
pp. 91-96
Author(s):  
Oksana V. Bondar ◽  
Denis V. Lebedev ◽  
Vesta D. Shevchenko ◽  
Anastas A. Bukharaev ◽  
Yury N. Osin ◽  
...  

2019 ◽  
Vol 9 (11) ◽  
pp. 2207 ◽  
Author(s):  
Christian Rodenbücher ◽  
Klaus Wippermann ◽  
Carsten Korte

Ionic liquids have become of significant relevance in chemistry, as they can serve as environmentally-friendly solvents, electrolytes, and lubricants with bespoke properties. In particular for electrochemical applications, an understanding of the interface structure between the ionic liquid and an electrified interface is needed to model and optimize the reactions taking place on the solid surface. As with ionic liquids, the interplay between electrostatic forces and steric effects leads to an intrinsic heterogeneity, as the structure of the ionic liquid above an electrified interface cannot be described by the classical electrical double layer model. Instead, a layered solvation layer is present with a structure that depends on the material combination of the ionic liquid and substrate. In order to experimentally monitor this structure, atomic force spectroscopy (AFS) has become the method of choice. By measuring the force acting on a sharp microfabricated tip while approaching the surface in an ionic liquid, it has become possible to map the solvation layers with sub-nanometer resolution. In this review, we provide an overview of the AFS studies on ionic liquids published in recent years that illustrate how the interface is formed and how it can be modified by applying electrical potential or by adding impurities and solvents.


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