Measurement of the surface free energy of bacterial cell surfaces and its relevance for adhesion

Abstract

An experimental technique is described to determine contact angles on bacterial layers deposited on cellulose triacetate filters. Measurements with water, water-n-propanol mixtures, and a-bromonaphthalene were employed to calculate surface free energies of various oral bacteria. Differences of 30 to 40 erg cm-2 were obtained for four different bacterial species isolated from the human oral cavity, if the concept of dispersion and polar surface free energies is applied. The free energies obtained were used to calculate interfacial free energies of adhesion of these bacteria from saliva onto tooth surfaces. Bacterial adhesion is energetically unfavorable, if the enamel surface free energy is less than 50 erg cm

Candida albicans aspects of novel silane system–coated titanium and zirconia implant surfaces

“…On zirconia surfaces a high SFE seems to increase the biofilm formation, while it tends to decrease the attachment of C. albicans on titanium surfaces. If the SFE is below 50 mJ/m 2 , it is more difficult for oral microorganisms to adhere to a surface (Busscher et al 1984). The SFE of all the different specimen groups is below 50 mJ/m 2 , and therefore, the adherence of C. albicans could be influence on every specimen.…”

“…Therefore, they prefer to bind to surfaces with high surface-free energy as well (Quirynen & Bollen 1995). If the surface-free energy is less than 50 mJ/m 2 , oral bacteria have more problems to adhere (Busscher et al 1984). Decreasing the value of surface-free energy influences the formation of biofilms on the coated surfaces significantly (Teughels et al 2006).…”

Characterization of the surface hydrophobicity of filamentous fungi

“…This was important because it was not our aim to measure the hydrophobicity of fungal spores. For contact angle measurements, bacteria are commonly grown in liquid media and afterwards transferred onto microporous membrane filters by filtration (Busscher et al, 1984b). This proved impractical for fungi.…”

Adhesion of Enterococcus faecalis 1131 grown under subinhibitory concentrations of ampicillin and vancomycin to a hydrophilic and a hydrophobic substratum

“…T W were measured on lawns of partially dehydrated bacteria using the sessile drop technique [8]. Brie£y, bac-teria suspended in demineralized water were layered onto 0.45-Wm pore size ¢lter (Millipore) using negative pressure.…”