Date of Award

Winter 2006

Document Type


Degree Name

Master of Science (MS)


Chemistry & Biochemistry

Committee Director

Xiao-Hong Nancy Xu

Committee Member

Kenneth Brown

Committee Member

Christopher Osgood

Committee Member

Jennifer Poutsma


Multi-drug resistance (MDR) has been reported in both prokaryotes and eukaryotes; the pathogenic gram-negative bacteria Pseudomonas aeruginosa can extrude a variety of structurally and functionally diverse substrates via a number of membrane transport systems leading to MDR. We have developed a novel nanoparticle assay to characterize both the membrane transport system composed of the MexAB-OprM efflux pump and the membrane permeability induced by antibiotics. Gold (Au) and silver (Ag) nanoparticles were investigated for use as probes to explore membrane transport in P. aeruginosa.

The surface plasmon absorption (color) of Au nanoparticle solutions was found to change in the presence of Tris(2, 2'-bipyridine)ruthenium(II). The color change was both size and temperature dependent. The change in surface plasmon absorption was caused by the formation of Au nanoparticle aggregates.

The surface plasmon absorption (color) of Ag nanoparticles was found to correlate with nanoparticle size and was readily observable using dark field microscopy. Ag nanoparticles were used to measure real-time transformation of cell permeability and MDR efflux dynamics of individual bacteria cells at nanometer resolution. The MDR efflux dynamics data was validated using time-course fluorescence of bulk cell populations.


In Copyright. URI: This Item is protected by copyright and/or related rights. You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s).