Quantifying Bacterial Adhesion through AFM
Terri A. Camesano
terric@wpi.edu
Department of Chemical Engineering, Life Sciences and Bioengineering Center at Gateway Park,
Worcester Polytechnic Institute, Worcester, MA 01609; USA
In the natural world, bacteria are much more likely to be found associated with a solid surface than suspended in a
liquid medium. Bacterial adhesion is important for many biomedical, environmental, and industrial applications.
For example, the attachment of bacteria to biomaterials or host tissue in the body are seen as the first steps in
initiating infections, such as catheter-related bloodstream infections or urinary tract infections. Atomic force
microscopy (AFM) can be used to characterize the biopolymers on a bacterial surface, such as lipopolysaccharides
(LPS), extracellular polysaccharides (EPS), fimbriae, and pili. In addition, AFM can be used to directly measure the
forces between bacterial cells and substrates of interest, such as bacteria-biomaterial interactions or bacteriaepithelial cell interactions. In this presentation, we will focus on a few examples related to bacterial adhesion
research:
1) Interactions between the Gram-positive pathogen Staphylococcus epidermidis and protein-coated
biomaterials, studied with AFM force measurements.
2) Interactions between Escherichia coli and uroepithelial cells, in the context of urinary tract infections.
3) Probing the physicochemical properties of bacterial biopolymers using steric modeling.
In my presentation, I will describe how to immobilize bacteria to an AFM tip to create a biological force probe, and
how to functionalize surfaces with proteins or cells. I will also describe models that can be applied to AFM data on
bacterial cells, so that we can gain more information on the fundamental properties of bacterial polymers involved
in the adhesion process.
References
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Emerson, R.J. IV, Bergstrom, T.S., Liu, Y., Soto, E.R., Brown, C.A., McGimpsey, W.G., and T.A. Camesano. A
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Gallardo-Moreno, A.M., Liu, Y., González-Martin, M.L., and T.A. Camesano. Atomic force microscopy analysis of
bacterial surface morphology before and after cell washing. Journal of Scanning Probe Microscopy. 2006, 1, 6373.
Atabek, A. and T.A. Camesano. An atomic force microscopy study of the effect of lipopolysaccharides and
extrapolymeric substances on the adhesion of Pseudomonas aeruginosa. Journal of Bacteriology. 2007,
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Liu, Y., Gallardo-Moreno, A.M., Pinzon-Arango, P.A., Reynolds, Y., Rodriguez, G., and T.A. Camesano. Cranberry
changes the physicochemical surface properties of E. coli and their adhesion with uroepithelial cells. Colloids
and Surfaces B: Biointerfaces. 2008 (In press)