Date of Award


Degree Type


Degree Name

Doctor of Philosophy (PhD)



First Advisor

Alexander Wei

Committee Chair

Alexander Wei

Committee Member 1

Bruce M. Applegate

Committee Member 2

Philip S. Low

Committee Member 3

Kavita Shah

Committee Member 4

Alexander Wei


Siderophores are low-molecular weight species utilized by bacteria for the sequestration of iron, an essential nutrient. Siderophores and their cognate receptors are considered to be virulence factors, due to their prominent role in pathogenicity. The work presented here focuses on ferrioxamine (FOx) as an “immutable” ligand for pathogen detection. A number of bacterial strains expressing high-affinity FOx receptors were identified by a proteomic BLAST search, and screened against microarrays patterned with FOx conjugates for detection using label-free optical imaging. Aspects such as inkjet printing and surface chemistry, iron-limiting conditions and bacterial selection protocols, and linker conjugate design were addressed and optimized.

The label-free optical imaging method is capable of both sensitive and rapid detection of select pathogens, dependent upon bacterial concentration and exposure time. Y. enterocolitica could be detected as low as 102 cfu/mL after a 1-hour exposure; conversely, several pathogenic bacteria could be detected after just 30 seconds of exposure at 107 cfu/mL. Additional studies on pathogen detection at refrigeration temperatures are discussed.