scholarly journals Intermolecular Forces and Enthalpies in the Adhesion of Streptococcus mutans and an Antigen I/II-Deficient Mutant to Laminin Films

2007 ◽  
Vol 189 (8) ◽  
pp. 2988-2995 ◽  
Author(s):  
Henk J. Busscher ◽  
Betsy van de Belt-Gritter ◽  
Rene J. B. Dijkstra ◽  
Willem Norde ◽  
Fernanda C. Petersen ◽  
...  
Keyword(s):  
Streptococcus Mutans ◽  
Parent Strain ◽  
Intermolecular Forces ◽  
Surface Proteins ◽  
Oral Streptococci ◽  
Adhesion Forces ◽  
Exterior Surface ◽  
Force Microscopy ◽  
Receptor Complexes ◽  
Atomic Force

ABSTRACT The antigen I/II family of surface proteins is expressed by most oral streptococci, including Streptococcus mutans, and mediates specific adhesion to, among other things, salivary films and extracellular matrix proteins. In this study we showed that antigen I/II-deficient S. mutans isogenic mutant IB03987 was nearly unable to adhere to laminin films under flow conditions due to a lack of specific interactions (0.8 × 106 and 1.1 × 106 cells cm−2 at pH 5.8 and 6.8, respectively) compared with parent strain LT11 (21.8 × 106 and 26.1 × 106 cells cm−2). The adhesion of both the parent and mutant strains was slightly greater at pH 6.8 than at pH 5.8. In addition, atomic force microscopy (AFM) experiments demonstrated that the parent strain experienced less repulsion when it approached a laminin film than the mutant experienced. Upon retraction, combined specific and nonspecific adhesion forces were stronger for the parent strain (up to −5.0 and −4.9 nN at pH 5.8 and 6.8, respectively) than for the mutant (up to −1.5 and −2.1 nN), which was able to interact only through nonspecific interactions. Enthalpy was released upon adsorption of laminin to the surface of the parent strain but not upon adsorption of laminin to the surface of IB03987. A comparison of the adhesion forces in AFM with the adhesion forces reported for specific ligand-receptor complexes resulted in the conclusion that the number of antigen I/II binding sites for laminin on S. mutans LT11 is on the order of 6 × 104 sites per organism and that the sites are probably arranged along exterior surface structures, as visualized here by immunoelectron microscopy.

scholarly journals In-Situ Investigation on Nanoscopic Biomechanics of Streptococcus mutans at Low pH Citric Acid Environments Using an AFM Fluid Cell

2020 ◽  
Vol 21 (24) ◽  
pp. 9481
Author(s):  
Linh Thi Phuong Nguyen ◽  
Bernard Haochih Liu
Keyword(s):  
Citric Acid ◽  
Streptococcus Mutans ◽  
Resistance Mechanisms ◽  
Adhesion Forces ◽  
Force Microscopy ◽  
Atomic Force ◽  
High Adhesion ◽  
Acid Shock ◽  
In Situ Investigation ◽  
Fluid Cell

Streptococcus mutans (S. mutans) is widely regarded as the main cause of human dental caries via three main virulence factors: adhesion, acidogenicity, and aciduricity. Citric acid is one of the antibiotic agents that can inhibit the virulence capabilities of S. mutans. A full understanding of the acidic resistance mechanisms (ARMs) causing bacteria to thrive in citrate transport is still elusive. We propose atomic force microscopy (AFM) equipped with a fluid cell to study the S. mutans ARMs via surface nanomechanical properties at citric acid pH 3.3, 2.3, and 1.8. Among these treatments, at pH 1.8, the effect of the citric acid shock in cells is demonstrated through a significantly low number of high adhesion zones, and a noticeable reduction in adhesion forces. Consequently, this study paves the way to understand that S. mutans ARMs are associated with the variation of the number of adhesion zones on the cell surface, which is influenced by citrate and proton transport. The results are expected to be useful in developing antibiotics or drugs involving citric acid for dental plaque treatment.

scholarly journals Role of Silver Ions in Destabilization of Intermolecular Adhesion Forces Measured by Atomic Force Microscopy in Staphylococcus epidermidis Biofilms

2005 ◽  
Vol 49 (12) ◽  
pp. 4853-4859 ◽  
Author(s):  
K. C. Chaw ◽  
M. Manimaran ◽  
Francis E. H. Tay
Keyword(s):  
Atomic Force Microscopy ◽  
Staphylococcus Epidermidis ◽  
Extracellular Polymeric Substances ◽  
Hydrophobic Interactions ◽  
Silver Ions ◽  
Intermolecular Forces ◽  
Adhesion Forces ◽  
Force Microscopy ◽  
Atomic Force ◽  
Biofilm Matrix

ABSTRACT In this paper, we report on the potential use of atomic force microscopy (AFM) as a tool to measure the intermolecular forces in biofilm structures and to study the effect of silver ions on sessile Staphylococcus epidermidis cell viability and stability. We propose a strategy of destabilizing the biofilm matrix by reducing the intermolecular forces within the extracellular polymeric substances (EPSs) using a low concentration (50 ppb) of silver ions. Our AFM studies on the intermolecular forces within the EPSs of S. epidermidis RP62A and S.epidermidis 1457 biofilms suggest that the silver ions can destabilize the biofilm matrix by binding to electron donor groups of the biological molecules. This leads to reductions in the number of binding sites for hydrogen bonds and electrostatic and hydrophobic interactions and, hence, the destabilization of the biofilm structure.

Nanoscale adhesion forces between the fungal pathogen Candida albicans and macrophages

2016 ◽  
Vol 1 (1) ◽  
pp. 69-74 ◽  
Author(s):  
Sofiane El-Kirat-Chatel ◽  
Yves F. Dufrêne
Keyword(s):  
Atomic Force Microscopy ◽  
Candida Albicans ◽  
Immune Cells ◽  
Fungal Pathogen ◽  
Fungal Pathogens ◽  
Adhesion Forces ◽  
Force Microscopy ◽  
Atomic Force

We establish atomic force microscopy as a new nanoscopy platform for quantifying the forces between fungal pathogens and immune cells.

A Cell's Perspective of its Culture Surface

2007 ◽  
Vol 1060 ◽  
Author(s):  
Ruchirej Yongsunthon ◽  
David E. Baker ◽  
Wendy A. Baker ◽  
Theresa Chang ◽  
Wanda J. Walczak ◽  
...  
Keyword(s):  
Culture Media ◽  
Preliminary Investigation ◽  
Surface Proteins ◽  
Force Microscopy ◽  
Driving Mechanisms ◽  
Atomic Force ◽  
Debye Shielding ◽  
Culture Surface ◽  
Substrate Surfaces ◽  
Functionalized Tips

ABSTRACTAtomic Force Microscopy (AFM) was employed to probe the internal structure of living HepG2/C3A cells grown on various commercially-available substrates. In order to understand the driving mechanisms behind the different cell morphologies, the surface properties of these substrates was characterized with AFM and related techniques. The roughness of a 10μm×10μm region of a series of substrates was determined and found to be independent of both coating and culture media, with the exception of thick hydrogel-like coatings. Probing with functionalized tips could not distinguish relative degrees of hydrophobicity under cell culture media, presumably because Debye shielding masks the substrate surfaces. Force spectroscopy was performed on the surfaces to determine exposed surface proteins/polymers intrinsic to the substrate and adsorbed from culture media. Preliminary investigation of cell-mediated substrate reconstruction suggests that the cells secrete large (1000kDa) polymeric molecules at the substrate interface.

scholarly journals A modular atomic force microscopy approach reveals a large range of hydrophobic adhesion forces among bacterial members of the leaf microbiota

2019 ◽  
Vol 13 (7) ◽  
pp. 1878-1882 ◽  
Author(s):  
Maximilian Mittelviefhaus ◽  
Daniel B. Müller ◽  
Tomaso Zambelli ◽  
Julia A. Vorholt
Keyword(s):  
Atomic Force Microscopy ◽  
Large Range ◽  
Adhesion Forces ◽  
Force Microscopy ◽  
Atomic Force

scholarly journals AFM and FluidFM Technologies: Recent Applications in Molecular and Cellular Biology

Scanning ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Mohamed Yassine Amarouch ◽  
Jaouad El Hilaly ◽  
Driss Mazouzi
Keyword(s):  
Single Cell ◽  
Protein Interactions ◽  
Single Cells ◽  
Cardiac Cells ◽  
Cellular Biology ◽  
Adhesion Forces ◽  
Cell Organelles ◽  
Force Microscopy ◽  
Imaging Tool ◽  
Atomic Force

Atomic force microscopy (AFM) is a widely used imaging technique in material sciences. After becoming a standard surface-imaging tool, AFM has been proven to be useful in addressing several biological issues such as the characterization of cell organelles, quantification of DNA-protein interactions, cell adhesion forces, and electromechanical properties of living cells. AFM technique has undergone many successful improvements since its invention, including fluidic force microscopy (FluidFM), which combines conventional AFM with microchanneled cantilevers for local liquid dispensing. This technology permitted to overcome challenges linked to single-cell analyses. Indeed, FluidFM allows isolation and injection of single cells, force-controlled patch clamping of beating cardiac cells, serial weighting of micro-objects, and single-cell extraction for molecular analyses. This work aims to review the recent studies of AFM implementation in molecular and cellular biology.

scholarly journals Adhesion force mapping on wood by atomic force microscopy: influence of surface roughness and tip geometry

2016 ◽  
Vol 3 (10) ◽  
pp. 160248 ◽  
Author(s):  
X. Jin ◽  
B. Kasal
Keyword(s):  
Surface Roughness ◽  
Atomic Force Microscopy ◽  
Wood Surface ◽  
Adhesion Force ◽  
Data Interpretation ◽  
Natural Fibre ◽  
Force Distribution ◽  
Adhesion Forces ◽  
Force Microscopy ◽  
Atomic Force

This study attempts to address the interpretation of atomic force microscopy (AFM) adhesion force measurements conducted on the heterogeneous rough surface of wood and natural fibre materials. The influences of wood surface roughness, tip geometry and wear on the adhesion force distribution are examined by cyclic measurements conducted on wood surface under dry inert conditions. It was found that both the variation of tip and surface roughness of wood can widen the distribution of adhesion forces, which are essential for data interpretation. When a common Si AFM tip with nanometre size is used, the influence of tip wear can be significant. Therefore, control experiments should take the sequence of measurements into consideration, e.g. repeated experiments with used tip. In comparison, colloidal tips provide highly reproducible results. Similar average values but different distributions are shown for the adhesion measured on two major components of wood surface (cell wall and lumen). Evidence supports the hypothesis that the difference of the adhesion force distribution on these two locations was mainly induced by their surface roughness.

scholarly journals Impacts of Natural Organic Matter Adhesion on Irreversible Membrane Fouling during Surface Water Treatment Using Ultrafiltration

Membranes ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 238
Author(s):  
Fangshu Qu ◽  
Zhimeng Yang ◽  
Shanshan Gao ◽  
Huarong Yu ◽  
Junguo He ◽  
...  
Keyword(s):  
Organic Matter ◽  
Surface Water ◽  
Natural Organic Matter ◽  
Membrane Fouling ◽  
Adhesion Forces ◽  
Cake Filtration ◽  
Force Microscopy ◽  
Surface Water Treatment ◽  
Atomic Force ◽  
Colloidal Probes

To understand impacts of organic adhesion on membrane fouling, ultrafiltration (UF) membrane fouling by dissolved natural organic matter (NOM) was investigated in the presence of background cations (Na+ and Ca2+) at typical concentrations in surface water. Moreover, NOM adhesion on the UF membrane was investigated using atomic force microscopy (AFM) with colloidal probes and a quartz crystal microbalance with dissipation monitoring (QCM-D). The results indicated that the adhesion forces at the NOM-membrane interface increased in the presence of background cations, particularly Ca2+, and that the amount of adhered NOM increased due to reduced electrostatic repulsion. However, the membrane permeability was almost not affected by background cations in the pore blocking-dominated phase but was aggravated to some extent in the cake filtration-governed phase. More importantly, the irreversible NOM fouling was not correlated with the amount of adhered NOM. The assumption for membrane autopsies is doubtful that retained or adsorbed organic materials are necessarily a primary cause of membrane fouling, particularly the irreversible fouling.

scholarly journals Nanoscale mapping of dielectric properties based on surface adhesion force measurements

2018 ◽  
Vol 9 ◽  
pp. 900-906 ◽  
Author(s):  
Ying Wang ◽  
Yue Shen ◽  
Xingya Wang ◽  
Zhiwei Shen ◽  
Bin Li ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Dielectric Properties ◽  
Adhesion Force ◽  
Model Systems ◽  
Adhesion Forces ◽  
Surface Adhesion ◽  
Storage Devices ◽  
Force Microscopy ◽  
Atomic Force

The detection of local dielectric properties is of great importance in a wide variety of scientific studies and applications. Here, we report a novel method for the characterization of local dielectric distributions based on surface adhesion mapping by atomic force microscopy (AFM). The two-dimensional (2D) materials graphene oxide (GO), and partially reduced graphene oxide (RGO), which have similar thicknesses but large differences in their dielectric properties, were studied as model systems. Through direct imaging of the samples with a biased AFM tip in PeakForce Quantitative Nano-Mechanics (PF-QNM) mode, the local dielectric properties of GO and RGO were revealed by mapping their surface adhesion forces. Thus, GO and RGO could be conveniently differentiated. This method provides a simple and general approach for the fast characterization of the local dielectric properties of graphene-based materials and will further facilitate their applications in energy generation and storage devices.

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