Force Measurements between Bacteria and Poly(ethylene glycol)-Coated Surfaces

Abstract

The atomic force microscope (AFM) was used to directly measure the forces of interaction between E. coli D21 bacteria and hydrophilic glass or hydrophobic N-octadecyltrichlorosilane (OTS)-treated glass substrates coated with the block copolymers, poly(ethylene glycol) (PEG)-lysine dendron or Pluronic F127 surfactant, respectively. Short-range repulsive interactions between bacterial cells and substrates coated with the block copolymers were detected by the AFM over distances of separation comparable to the extended length of the PEG polymer chains. In contrast, glass and OTS-treated glass devoid of PEG-lysine dendron or Pluronic F127 exerted long-range attractive forces on E. coli D21 bacteria. Thus, polymeric brush layers appear to not only block the long-range attractive forces of interaction between bacteria and substrates but also introduce repulsive steric effects.

Inhibition of adhesion of yeasts and bacteria by poly(ethylene oxide)-brushes on glass in a parallel plate flow chamber

“…However, PEO with a molar mass of 3500 Da rendered the surface resistant to staphylococcal adhesion. Another study showed that surfaces with PEO chains with a molecular mass of 4500 and 20 000 Da blocked the adhesion of E. coli D 21 (Razatos et al, 2000). Surprisingly, it has also been found that a selfassembled monolayer of PEO with only six PEO units is able to prevent the adhesion of Sta.…”

“…Therewith, a PEO-brush forms a steric barrier preventing close approach and thus attenuates the attractive Lifshitz-Van der Waals interaction between the protein and the surface. PEO-coatings have also been investigated for their ability to prevent bacterial adhesion (Park et al, 1998;Razatos et al, 2000;Ista et al, 1996;Bridgett et al, 1992). Varying results have been obtained, ranging from reductions in bacterial adhesion of 98 % (Razatos et al, 2000;Ista et al 1996), 90-98 % (Bridgett et al, 1992) and between 0 and 90 % (Park et al, 1998).…”

“…PEO-coatings have also been investigated for their ability to prevent bacterial adhesion (Park et al, 1998;Razatos et al, 2000;Ista et al, 1996;Bridgett et al, 1992). Varying results have been obtained, ranging from reductions in bacterial adhesion of 98 % (Razatos et al, 2000;Ista et al 1996), 90-98 % (Bridgett et al, 1992) and between 0 and 90 % (Park et al, 1998). These studies, however, have used only a small number of strains and the adhesion methodology employed involved dipping and slight rinsing, which may also cause detachment and accompanying low adhesion numbers (Gò mez-Suárez et al, 2001).…”

Force measurements with the atomic force microscope: Technique, interpretation and applications

“…First attempts in this direction were made by Razatos et al [980] who demonstrated that it is possible to coat silicon nitride AFM cantilevers including the tip with a layer of E. coli cells, if the cells were fixed by glutaraldehyde treatment. The authors took advantage of such functionalized tips to study the adhesion of E. coli [386,981] (see also Ref. [982]).…”

Atomic Force Microscopy

“…A similar study has been done using AFM to find relation between surface charge heterogeneity and the deposition rates of colloids during their transport in porous media (Shellenberger and Logan, 2002). AFM has been used to understand the role polysaccharides present on bacterial cells play by offering steric hindrance and blocking the long range attractive forces between bacteria and substrata (Razatos et al, 2000).…”