Funded by: PPG, Inc., January 15, 2002 - December, 2002

Contact information: Phone: 814-863-7908, Email: blogan@psu.edu

Investigators: Bruce Logan, Penn State University; Cory Steffak, PPG Inc.

Abstract

Bacterial attachment can occur on any surface. Bacteria, as well as other organic debris, are abundant in both aqueous and atmospheric systems. Typical bacteria concentrations even in very clean streams vary from 104 to 106 cells per mL and can average 106 to 107 per mL in some lake and marine waters. Bacteria are also abundant in the air. Total culturable cell counts in houses in temperate zones average 900 per cubic meter, with fungal spores reaching somewhat higher concentrations of 103 m-3. These are likely underestimates (by two to three orders-of-magnitude) due to a lack of sufficient techniques to fully ascertain bacterial counts.

Biofouling of surfaces has large industrial and economic consequences. The formation of a biofilm can lead to a complete change in the interfacial properties of the surface (i.e. the exposed surface) and result in the loss of system performance. Biofouling is a problem in diverse areas such as medical implants, industrial heat exchangers, and marine surfaces. Bacterial adhesion to different surfaces has been examined by the Logan group using several different techniques developed in our laboratory, including; fluorescent microscopy, large column tests, and mini-column tests with bacteria tagged with radioisotopes. We have looked at bacteria, phytoplankton and microsphere adhesion to a variety of surfaces including many different types of fibers (glass, nylon, celluose, polycarbonate), mesh, screens, glass, and soils. We have merged these approaches with hydrodynamic models in order to quantify initial adhesion event.

A collaborative effort is being undertaken between Penn State researchers, led by Dr. Bruce Logan, and PPG to investigate bacterial adhesion to various uncoated and coated surfaces. This work is being performed at Penn State in conjunction with an existing multi-investigator project funded for five years by the National Science Foundation. It is expected that this research will provide a greater understanding of the factors that promote adhesion so that they may be controlled.