Detection and Destruction of Escherichia Coli Bacteria and Bacteriophage Using Biofunctionalized Nanoshells
Abstract (Summary)The ability to detect chemical and biological agents is arguably one of the highest priority technical challenges today. The capability to obtain specific information at and near single-molecule resolution is the ultimate goal in chemical and biological agent detection. Metallic nanostructures, nanoshells and nanorods in particular, are attractive substrates because of their plasmonic properties. Combining the specificity of biomolecular recognition with these nanostructures might lead to increased sensitivity and selectivity. Localization of biological recognition motifs to the surface of these nanostructures could provide a mechanism for highly specific and directed energy transfer when bound to its target. This study utilizes nanoshells functionalized with antibodies specific for Escherichia coli, and investigates at both the microscopic and macroscopic scales the ability of these biofunctionalized nanoshells to bind and destroy their target micro-organism when excited using 808 nm near infrared laser radiation. Extension of the technique to Bacillus subtilis spores as well as bacteriophage specific to Escherichia coli are also explored. The bacteriophage is a viral surrogate, and provides a means to explore proof of principle of the interactions between nanoshells and viruses. It is demonstrated that appropriately biofunctionalized nanoshells recognize and bind to their target species, and that the nanoshell successfully couples the energy transfer from an IR laser to the target species. A ratio of nanoshells to Escherichia coli of ~10^4 for a 50% bacterial cell survival rate is determined, and a possible mechanism for this is discussed. Finally, this ratio is found to decrease by 4-5 orders of magnitude for the case of two Escherichia coli bacteriophage considered, and the significance of this is described.
School:Wright State University
School Location:USA - Ohio
Source Type:Master's Thesis
Date of Publication:01/01/2007