Surface thermodynamics of bacterial adhesion

Abstract

The adhesion of five strains of bacteria, i.e., Staphylococcus aureus (strain 049), Staphylococcus epidermidis (strain 047), Escherichia coli (strains 055 and 2627), and Listeria monocytogenes, to various polymeric surfaces was studied. The design of the experimental protocol was dictated by thermodynamic considerations. From the thermodynamic model for the adhesion of small particles from a suspension onto a solid substratum, it follows that the extent of adhesion is determined by the surface properties of all three phases involved, i.e., the surface tensions of the adhering particles, of the substrate, and of the suspending liquid medium. In essence, adhesion is more extensive to hydrophilic substrata (i.e., substrata of relatively high surface tension) than to hydrophobic substrata, when the surface tension of the bacteria is larger than that of the suspending medium. When the surface tension of the suspending liquid is larger than that of the bacteria, the opposite pattern of behavior prevails. Suspensions of bacteria at a concentration of 10(8) microorganisms per ml were brought into contact with several polymeric surfaces (Teflon, polyethylene, polystyrene, and acetal and sulfonated polystyrene) for 30 min at 20 degrees C. After rinsing, the number of bacteria adhering per unit surface area was determined by image analysis. The surface tension of the suspending medium. Hanks balanced salt solution, was modified through the addition of various amounts of dimethyl sulfoxide. It was found that the number of bacteria adhering per unit surface area correlates well with the thermodynamic predictions and that these data may be used to determine the surface tension of the different bacterial species. The surface tensions of the bacteria obtained in this fashion are in excellent agreement with those obtained by other methods.

Microscopic Visualization of Insect Cell‐Bubble Interactions. I: Rising Bubbles, Air‐Medium Interface, and the Foam Layer

“…This change in AG can be related to the interfacial tensions of the surfaces involved. Such a model was developed by Absolom et al (1983) for bacterial adhesion. As predicted by their model, and confirmed by experimental work, changes in the interfacial tension of the suspending liquid, and thereby changes in AG, can significantly change the amount of bacteria that adheres to surfaces.…”

The protective effect of specific medium additives with respect to bubble rupture

“…Bacterial cell adhesion to a solid substrate is also nonspecific, as supported by the experiments conducted by Absolom et al They studied the phenomenon of bacterial cell adhesion to various polymeric surfaces and proposed a relationship based on thermodynamic considerations to predict the possibility of the cell-solid adhesion. According to Absolom et al * adhesion of the cells to the solid surface is dependent on the interfacial tensions (y) between the three interacting phases: the solid (s), the bacteria (b), and the surrounding liquid (1). The possibility of cell adhesion to the solid surface is determined by the change in free energy for the process of bacterial cell adhesion (AFadh) to the solid substrate, and the thermodynamic relationship that determines the change in the free energy of the process is given by A negative value of AFadh indicates that the process of adhesion is thermodynamically favorable, whereas a positive value indicates that the process is unfavorable.…”

Thermodynamic approach to explain cell adhesion to air–medium interfaces

“…Consider the case of a cell suspended in a bioreactor that is sparged with air as shown in Figure 1. Three different phases coexist in the bioreactor: the cells (c), the vapor phase (v), and the liquid medium (1). There are, correspondingly, three different interfacial tensions: (i) interfacial tension between cell and vapor (yo), (ii) interfacial tension between cell and liquid medium (YJ, and (iii) interfacial tension between liquid and vapor (yJ.…”

“…Here, yI2 can be expressed as (A. 1) According to Owen and Wendt,21 the value of ySr is expressed by In Equation (A.2), 8 and ylv can be determined experimentally, and from these values y,, can be calculated. Suitable assumptions regarding the values of yt2 and yf2 can be made depending on the polarity of the system.…”