Development of Fluorescence-Enabled Electrochemical Microscopy for Electrochemical Imaging and Detection

Abstract

This dissertation discusses various aspects of the fundamental development of fluorescence-enabled electrochemical microscopy (FEEM) into a useful analytical tool for electrochemical imaging and detection. Chapter 1 briefly introduces the technique of FEEM and discusses how it can be used to overcome current challenges in electrochemical imaging and low-level electrochemical sensing. Chapter 2 discusses the development of a new fluorogenic indicator reaction that makes possible the detection of electrochemical reduction reactions. This chapter also introduces a new fluorophore quenching scheme used to improve the spatial and temporal resolution of FEEM imaging. FEEM imaging is further developed in Chapter 3, which demonstrates the use of a bipolar electrode array to image dynamic concentration gradients in 2- and 3-dimensions. Chapter 4 moves on to a discussion of the use of electrogenerated chemiluminescence (ECL) as an optical reporter on closed bipolar electrodes as an alternative to fluorescence. This chapter highlights the importance of carefully selecting the size-geometry of the bipolar electrode system when using an optical readout. Lastly, Chapters 5 and 6 introduce a redox particle detection scheme for use in quantifying the detection limit of FEEM. Chapter 5 focuses on the interesting coupled electrochemical and fluorescence properties of methylene blue-modified polystyrene microspheres. Chapter 6 discusses using single Ag nanoparticles for detection limit quantification and early attempts and problems in doing so. The chapter then closes with a discussion of the interesting dynamic behavior observed during the oxidation of single Ag nanoparticles.