Influence of pH on the suspension stability of some oral bacteria

The purpose of the present study was to investigate the suspension stability of some oral bacteria at some clinically relevant pH levels. Through determinations of the electrophoretic mobility and sedimentation behavior at pH 5, 6, and 7, it was shown that within this pH range estimations of both the zeta-potentials and colloidal stability were pH-dependent for the bacteria and bacterial suspensions tested. The observations are in line with the DLVO theory for lyophobic sols and indicate that bacteria behave like colloidal particles when suspended in certain media. The colloidal behavior further seemed to vary in relation to bacterial species and strains.