Assessing bacterial adhesion using DLVO and XDLVO theories and the jet impingement technique

In this study, the adhesion of two bacterial strains (Pseudomonas stutzeri PS, and Staphylococcus epidermidis, SE) to the glass and the indium tin oxide (ITO)-coated glass surfaces was examined qualitatively and quantitatively using the theoretical approaches and the jet impingement technique. A comparison between the DLVO and the extended DLVO (XDLVO) theories showed that the XDLVO predictions of bacterial adhesion and its reversibility are more accurate than DLVO predictions. The adhesion tests revealed that PS bacteria has much better adhesion rate than SE bacteria to both material surfaces, as predicted by XDLVO approach. Also both bacterial strains adhered better to the hydrophobic ITO-coated glass than to the hydrophilic glass surface, as predicted theoretically. Moreover, the microjet impingement technique was used not only to assess the bacterial adhesion strength on both materials, but also to verify the adhesion reversibility. The detachment stress values demonstrated that PS bacterial cells adhered strongly and irreversibly in the primary energy minimum, while SE bacterial cells adhered weakly and reversibly in the secondary energy minimum on both substrata surfaces. Also, the adhesion of both bacterial strains was found better and stronger on the hydrophobic ITO-coated glass surface than on the hydrophilic glass surface.