The influence of surface topography on bacterial adhesion has been investigated using a range spatially organized microtopographic patterns generated polydimethylsiloxane (PDMS) and three unrelated strains. results presented indicate that cells actively choose their position to settle, differentiating upper lower areas in all the evaluated. Such selective depends cells’ size shape relative dimensions topographical features hydrophobicity/hydrophilicity. Moreover, it was found topographies...

ABSTRACT Atomic force microscopy (AFM) has emerged as a powerful technique for mapping the surface morphology of biological specimens, including bacterial cells. Besides creating topographic images, AFM enables us to probe both physicochemical and mechanical properties cell surfaces on nanometer scale. For AFM, cells need be firmly anchored substratum in order withstand friction forces from silicon nitride tip. Different strategies immobilization bacteria have been described literature. This...

The cell envelope of gram-negative bacteria is responsible for many important biological functions: it plays a structural role, accommodates the selective transfer material across wall, undergoes changes made necessary by growth and division, transfers information about environment into cell. Thus, an accurate quantification mechanical properties required not only to understand physiological processes but also help elucidate relationship between surface structure function. We have used...

Exopolymers are thought to influence bacterial adhesion surfaces, but the time-dependent nature of molecular-scale interactions biopolymers with a surface poorly understood. In this study, forces between two proteins and polysaccharide [Bovine serum albumin (BSA), lysozyme, or dextran] colloids (uncoated BSA-coated carboxylated latex microspheres) were analyzed using colloid probe atomic force microscopy (AFM). Increasing residence time an uncoated microsphere on consistently increased...

We used a novel atomic force microscopy (AFM)-based technique to compare the local viscoelastic properties of individual gram-negative (Escherichia coli) and gram-positive (Bacillus subtilis) bacterial cells. found that cells are well described by three-component mechanical model combines an instantaneous elastic response delayed response. These experiments have allowed us investigate relationship between structure composition cell envelope. In addition, this is first report in which role...

Bacterial cell envelopes are remarkable biological structures that allow cells to adapt and survive changes in their external environment while maintaining mechanical integrity as the grow divide. We review efforts characterize properties of bacterial envelope, we highlight recent advances measurement techniques for individual have led a more complete understanding. In addition elastic behavior, walls also demonstrate time dependent response externally applied forces such properly described...

Mechano-bactericidal nanomaterials rely on their mechanical or physical interactions with bacteria and are promising antimicrobial strategies that overcome bacterial resistance. However, the real effect of versus chemical action activity is under debate. In this paper, we quantify forces necessary to produce critical damage cell wall by performing simultaneous nanoindentation fluorescence imaging single cells. Our experimental setup allows puncturing an immobilized bacterium tip atomic force...

Variations in surface hydrophobicity of six Lactobacillus strains with and without an S-layer upon changes ionic strength are derived from contact angle measurements low- high-ionic-strength aqueous solutions. Cell changed response to three out the strains, offering these a versatile mechanism adhere different surfaces. The dynamic behavior cell could be confirmed for two selected by measuring interaction force between hydrophobic hydrophilic tips use atomic microscopy.

Bacterial adhesion to substratum surfaces is determined by the combined action of a large number different interactions, which have hitherto been inferred from macroscopic cell surface properties, such as electrostatic double-layer forces, hydrophobic hydrogen bonding, and steric interactions. The origin these interactions arises molecular level, but nevertheless they always estimated point view. bacterial hydrophobicity, for instance, commonly water contact angles on lawns, charge...

Bacterial adhesion to surfaces does not always proceed according theoretical expectations. Discrepancies are often attributed surface heterogeneities that provide localized, favorable sites for bacterial attachment. The presence of these deposition bacteria, however, has never been directly measured. Atomic force microscopy (AFM) was used quantify the distribution attractive on clean substrata. Surfaces silica and three different metal oxides mapped by with regular or colloidal AFM tips...

Propolis is a natural product obtained from hives. Its chemical composition varies depending on the flora of its surroundings, but nevertheless, common for all types propolis, they exhibit remarkable biological activities. The aim this study was to investigate and antimicrobial activity novel Spanish Ethanolic Extract (SEEP). It found that new SEEP contains high amounts polyphenols (205 ± 34 mg GAE/g), with unusually more than half flavonoid class (127 19 QE/g). Moreover, detailed analysis...

Application of physico-chemical models to describe bacterial adhesion surfaces has hitherto only been partly successful due the structural and chemical heterogeneities surfaces, which remain largely unaccounted for in macroscopic characterizations cell surfaces. In this study, authors attempted correlate microscopic a collection nine Streptococcus mitis strains negatively charged, hydrophilic silicon nitride tip an atomic force microscope (AFM) with glass parallel-plate flow chamber. The...

We have used atomic force microscopy (AFM) to measure the viscoelastic properties of individual Escherichia coli K12 cells under fully hydrated conditions by collecting AFM force–indentation and force–time curves. Spherical colloidal tips were reduce local strain ensuring that measurements performed in linear regime. find exhibit a time-dependent response constant compressive applied tip. The results are interpreted using standard solid model which describes both an instantaneous delayed...

The electrical characterization of surfaces in terms the zeta potential (ζ), i.e., electric contributing to interaction energy, is major importance a wide variety industrial, environmental and biomedical applications which integration any material with surrounding media initially mediated by physico-chemical properties its outer surface layer. Among different existing electrokinetic techniques for obtaining ζ, streaming (Vstr) current (Istr) are important when dealing flat-extended samples....

The new and simple numerical procedure presented in this paper to analyze bacterial growth will possibly allow the identification of true differences efficacy among antimicrobial drugs for their applications human health, food security, environment, others. It further provides insight into predictive microbiology, likely helping development proper mathematical models predict course under diverse circumstances.

Staphylococcus epidermis has emerged as the main causative agent of medical device-related infections. Their major pathogenicity factor lies in its ability to adhere surfaces and proliferate into biofilms, which increase their resistance antibiotics. The objective this study was evaluate use mechanism action an ethanolic extract Spanish propolis (EESP) a potential alternative for preventing biofilm-related infections caused by S. epidermidis. chemical composition is reported antibacterial...

Abstract Increased bacterial resistance to traditional antimicrobial agents has prompted the use of natural products with properties such as propolis, extensively employed since ancient times. However, chemical composition propolis extracts is extremely complex and been shown vary depending on region season collection, due variations in flora from which pharmacological substances are obtained, being therefore essential for their activity be checked before use. For this purpose, we evaluate...