Conjugated oligoelectrolytes are finding innovative applications in optical detection. They contain ionic pendent groups that integrate water solubility to the light harvesting properties of the conjugated backbone. These pendent groups also offer an opportunity to bind an electrostatic counterpart, for example, a Forster resonance energy transfer (FRET) unit. The combination of an oligoelectrolyte donor and a FRET acceptor affords a highly sensitive optical probe that can be employed in biodetection. Microbial detection and identification was particularly targeted due to its relevance to medicine, biosecurity, and the supply of food and water. This dissertation describes the use of conjugated oligoelectrolytes to generate nanoassemblies for use in bacterial identification and bacterial growth history characterization.

An array of nanoassemblies was prepared by electrostatically complexing a cationic oligoelectrolyte with different fluorescein--labeled single--stranded DNA. Studies using atomic force microscopy and fluorescence microscopy confirm their nano-scale size and interaction with the bacterial surface, respectively. The effect of buffer concentration, charge ratio, and oligoelectrolyte concentration used to generate the nanoassemblies, on bacterial response was investigated and optimized using the central composite design and a hybrid artificial neural network model.

Excitation of the nanoassemblies produced a photoluminescent spectrum composed of oligoelectrolyte emission and sensitized fluorescein emission. Introduction of bacteria to the nanoassemblies gave rise to perturbations in the photoluminescent spectrum. The collective differential response of the nanoassemblies was used to create a signature pattern that was utilized to identify the bacteria or characterize the bacterial growth history.