Date of Award

Summer 7-29-2021

Document Type


Degree Name

Master of Science (MS)



First Advisor

Dr Santimukul Santra

Second Advisor

Dr Irene Zegar

Third Advisor

Dr Phillip Harries


Increasing foodborne illnesses have led to global health and economic burdens. E. coli O157:H7 is one of the most common disease-provoking pathogens and known to be lethal Shiga toxin-producing E. coli (STEC) strains. With a low infection dose in addition to person-to-person transmission, STEC infections are easily spread. As a result, specific and rapid testing methods to identify foodborne pathogens are urgently needed. Nanozymes have emerged as enzyme-mimetic nanoparticles, demonstrating intrinsic catalytic activity that could allow for rapid, specific, and accurate pathogen identification in the agrifood industry. In this study, we explored a trimodal nanoplatform utilizing colorimetric kinetics based on the traditional ELISA assay with the synergistic properties of gold and iron oxide nanozymes, replacing the conventional horseradish peroxidase (HRP). We designed an easily interchangeable “ELISA sandwich” composed of a novel magneto-plasmonic nanosensor (MPnS) and with target antibodies (MPnS-Ab). Our experiments demonstrate a 100-fold increase in catalytic activity with the dual (magneto-plasmonic) nanozymes in comparison to HRP with observable color changes within 15 minutes. Results further indicate our MPnS-Ab is highly specific for E. coli O157:H7. As nanozymes display more stability than natural enzymes, tunable activity, and multi-functionality, our platform could provide a customizable, low-cost assay that combines high specificity with rapid detection for a variety of pathogens.



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