Acquisition of a SurPASS Electrokinetic Analyzer

Lehigh University, Bethlehem PA

Investigators

Abstract

Brown, Derek CBET-0967076 This is a proposal for the acquisition of an Anton Paar SurPASS Electrokinetic Analyzer in support of the PIs NSF sponsored research examining the impacts of bacterial adhesion on cellular metabolic activity. The working hypothesis for this research area is that bacteria can take advantage of a link between cellular bioenergetics and the physiochemical charge regulation effect, which occurs as a surface containing acid/base functional groups (e.g., the bacterial cell surface) approaches another surface. As the bacterium approaches the surface, the charge regulation effect causes the charge and pH at the cell surface to vary as a function of separation distance. The hypothesis states that the change in pH at the cell surface can affect the proton motive force that forms across the bacterial membrane, with a resulting change in cellular ATP levels. They have had very good success in this research area to date, demonstrating that adhesion can both enhance and inhibit metabolic activity, depending on the charge nature of the adhering surface. They are now working validating the hypothesis by varying the surface charge of the adhering surface and comparing the experimental results to our model predictions. To model this system, they require accurate knowledge of the charge properties of the adhering surface. To date they have been using electrophoretic mobility (EM) measurements of finely crushed materials. While there are issues with the use of crushed materials, this approach has allowed them to determine the electrostatic properties of the adhering surface and use this data to model how adhesion affects the cellular metabolic activity. In order to both validate their working hypothesis and to develop materials that give a specific microbial response (e.g., enhance activity or inhibit biofilm formation), they are now preparing to examine a wide range of materials that unfortunately donʹt allow themselves to be finely crushed and analyzed via electrophoretic mobility measurements. In contrast to electrophoretic mobility instruments, which are designed to work with colloids, the SurPASS Electrokinetic Analyzer is designed to work with macroscopic solids. By measuring the streaming potential (or streaming current), the SurPASS provides the zeta potential as the primary information. Material that can be analyzed include granular media (e.g., sand, soil, glass and polymer beads), fibers, powders, and planar media (e.g., foils, membranes, glass and polymer sheets). The acquisition and use of this instrument will significantly enhance the output and productivity of the PIs research laboratory by allowing the determination of the electrostatic properties of macroscopic materials. This information will be used in the modeling of charge regulated surfaces and will enable experimental validation of the working hypothesis. Through this mechanism, this instrument will ultimately provide data that will impact the wide array of research fields involved with bacterial adhesion and surface colonization. Additional broader impacts related the acquisition and use of the SurPASS instrument span both research and education. This instrument will be made available to researchers at Lehigh University and other universities (most notably Lafayette College, an undergraduate institution located in nearby Easton, PA), and it will be used in research experiences of undergraduates and secondary school teachers.