Status of methods for assessing bacterial cell surface charge properties based on zeta potential measurements

Surface interfacial physiology is particularly important to unicellular organisms with regard to maintenance of optimal cell function. Bacterial cell surfaces possess net negative electrostatic charge by virtue of ionized phosphoryl and carboxylate substituents on outer cell envelope macromolecules which are exposed to the extracellular environment. The degree of peripheral electronegativity influences overall cell surface polarity and can be assessed on the basis of zeta potential which is most often determined by estimating the electrophoretic mobility of cells in an electric field. The purpose of this review is to provide bacteriologists with assistance as they seek to better understand available instrumentation and fundamental principles concerning the estimation of zeta potential as it relates to bacterial surface physiology.