The influence of surface chemistry on the kinetics and thermodynamics of bacterial adhesion

Abstract

This work is concerned with investigating the effect of substrate hydrophobicity and zeta potential on the dynamics and kinetics of the initial stages of bacterial adhesion. For this purpose, bacterial pathogens Staphylococcus aureus and Escherichia coli O157:H7 were inoculated on the substrates coated with thin thiol layers (i.e., 1-octanethiol, 1-decanethiol, 1-octadecanethiol, 16-mercaptohexadecanoic acid, and 2-aminoethanethiol hydrochloride) with varying hydrophobicity and surface potential. The time-resolved adhesion data revealed a transformation from an exponential dependence to a square root dependence on time upon changing the substrate from hydrophobic or hydrophilic with a negative zeta potential value to hydrophilic with a negative zeta potential for both pathogens. The dewetting of extracellular polymeric substances (EPS) produced by E. coli O157:H7 was more noticeable on hydrophobic substrates, compared to that of S. aureus, which is attributed to the more amphiphilic nature of staphylococcal EPS. The interplay between the timescale of EPS dewetting and the inverse of the adhesion rate constant modulated the distribution of E. coli O157:H7 within microcolonies and the resultant microcolonial morphology on hydrophobic substrates. Observed trends in the formation of bacterial monolayers rather than multilayers and microcolonies rather than isolated and evenly spaced bacterial cells could be explained by a colloidal model considering van der Waals and electrostatic double-layer interactions only after introducing the contribution of elastic energy due to adhesion-induced deformations at intercellular and substrate-cell interfaces. The gained knowledge is significant in the context of identifying surfaces with greater risk of bacterial contamination and guiding the development of novel surfaces and coatings with superior bacterial antifouling characteristics.

Electroactive 3D Printed Scaffolds Based on Percolated Composites of Polycaprolactone with Thermally Reduced Graphene Oxide for Antibacterial and Tissue Engineering Applications

“…In addition, the Rsk and Rsk values obtained were consistent with the topography studies performed on different types of surfaces reported in the literature [67][68][69]. The roughness of biomaterial at the nanometric level was also analyzed due to the implications for human cell and bacterial adhesion [62,63]. In bone cells, nanoscale morphology has been used to control cell growth inducing bone tissue formation, bone recovery, and even osseointegration [61,64].…”

“…Surface chemistry is essential for bacterial and cell adhesion, as it is widely reported that by decreasing the hydrophobicity of the surface, the adhesion of S. aureus can also be decreased [61][62][63][64][65][66]. By incorporating 10% wt of TrGO particles into the PCL polymer matrix, the hydrophobicity of the material decreased significantly from an average value of 113.3 ± 10 • to 74.8 ± 9 • (Figure 6a).…”

“…With the TrGO particles, hydrophilic functional groups were incorporated into the polymer composite, as previously discussed in XPS analysis (Figure 2a). The roughness of biomaterial at the nanometric level was also analyzed due to the implications for human cell and bacterial adhesion [62,63]. In bone cells, nanoscale morphology has been used to control cell growth inducing bone tissue formation, bone recovery, and even osseointegration [61,64].…”

“…This was due to the functional groups of hydrophilic of TrGO particles (C = O and C-O) after the thermal reduction of GO [54]. Bacteria with hydrophobic characteristics, such as S. aureus, contain hydrophobic proteins in their cell walls, such as carboxylic phosphatase and teichoic acids [63] so their adhesion prefers the hydrophobic surfaces [70]. Another important factor in bacterial adhesion to biomaterials is the morphology of surface topography.…”

Coating for preventing nonspecific adhesion mediated biofouling in salty systems: Effect of the electrostatic and van der waals interactions

“…Interestingly, the competitive interplay of electrostatic and vdW interactions in the anti‐fouling action of the coating has received little attention. This is quite surprising given several previous investigations on the effect of Derjaguin‐Landau‐Verwey‐Overbeek (DLVO) forces on bacterial adhesion to different surfaces [16–18]. In our model, the microorganism is simplistically represented as a charged lipid bilayer encapsulated vesicle‐like system (Fig.…”