Does Bacterial Elasticity Affect Adhesion to Polymer Fibers?

Abstract

The factors governing bacterial adhesion to substrates with different topographies are still not fully identified. The present work seeks to elucidate for the first time and with quantitative data the roles of bacterial elasticity and shape and substrate topography in bacterial adhesion. With this aim, populations of three bacterial species, P. aeruginosa DSM 22644, B. subtilis DSM 10, and S. aureus DSM 20231 adhered on flat substrates covered with electrospun polycaprolactone fibers of different diameters ranging from 0.4 to 5.5 μm are counted. Populations of bacterial cells are classified according to the preferred binding sites of the bacteria to the substrate. The colloidal probe technique was used to assess the stiffness of the bacteria and bacteria–polymer surface adhesion energy. A theoretical model is developed to interpret the observed populations in terms of a balance between stiffness and adhesion energy of the bacteria. The model, which also incorporates the radius of the fiber and the size and shape of the bacteria, predicts increased adhesion for a low level of stiffness and for a larger number of available bacteria–fiber contact points. Te adhesive propensity of bacteria depends in a nontrivial way on the radius of the fibers due to the random arrangement of fibers.

Influence of the Available Surface Area and Cell Elasticity on Bacterial Adhesion Forces on Highly Ordered Silicon Nanopillars

“…A multitude of different factors, including surface roughness and stiffness, feature geometry on a nano/microscale, and the subsequent available surface area, as well as chemical surface composition, contribute to bacterial adhesion. 5 Even though their general influence is well-established, 5 , 12 the mechanisms that determine the specific interaction of every individual factor with bacteria are still controversially discussed. As an example, for nanotopography and the resulting available surface area, it could be shown that increasing surface roughness and structures with feature sizes similar to bacteria support bacterial colonization.…”

Effects of Nickel Nanoparticles on Rhodococcus Cell Surface Morphology and Nanomechanical Properties

“…It is generally accepted [ 22 ] that an increase in the Young’s modulus, as a measure of the rigidity or elasticity of the cell wall, leads to a decrease in the adhesion efficiency of bacterial cells. However, in another study [ 7 ], treatment with hematite nanoparticles increased the rigidity of E. coli cells and caused the appearance of many adhesive sites on the cell surface.…”

“…On the other hand, a less rigid and more flexible hydrophobic cell wall contributed to the uptake of hydrocarbon substrates by Rhodococcus cells [ 20 ]. Contradictory literature data on the influence of nanometals on mechanical and rheological properties of bacterial cells are partially explained by technical variations in the AFM nanoindentation and structural heterogeneity of the bacterial cell surface, represented by macromolecules with varying degrees of hydrophobicity, electric charge and spatial organization, causing heterogeneity of rheological properties [ 7 , 22 ]. The specific molecular interactions that cause these mechanical forces are the result of a complex interplay of fundamental hydrophobic, electrostatic, van der Waals and hydrogen bonding forces [ 23 ].…”

“…The specific molecular interactions that cause these mechanical forces are the result of a complex interplay of fundamental hydrophobic, electrostatic, van der Waals and hydrogen bonding forces [ 23 ]. Nevertheless, the revealed adaptation features, such as cell hydrophobicity accompanied by the increased specific surface area and roughness, an increase in adhesion force and a decrease in Young’s modulus in response to nickel NPs, would determine Rhodococcus ’s efficient attachment to solid surfaces and degradation of hydrocarbon substrates [ 11 , 13 , 14 , 22 ]. Further research on the mechanisms of bacterial adaptation to metal NPs, such as changes in surface morphology (size and roughness) and nanomechanical properties will help to strengthen the advantages of Rhodococcus in biotechnology and environmental applications.…”

Regulation of photo triggered cytotoxicity in electrospun nanomaterials: role of photosensitizer binding mode and polymer identity

“…56 It has recently been suggested that bacterial elasticity and shape may also govern bacterial adhesion to substrates. 57 subtilis. 58 PAN-based NFs also demonstrated low fouling values for B. subtilis.…”