Over the past few years, our laboratory has developed a total internal reflection fluorescence microscopy (TIRFM) apparatus that enables in-situ, quantitative, and non-destructive molecular-level investigations of macromolecular adsorption and diffusion at the liquid-liquid interface. The apparatus is ideally suited for characterizing protein interactions at biomimetic interfaces, because it allows selective excitation of fluorescent species at and in the vicinity of the interface. We have recently modified the TIRFM flow cell for in-situ electrochemical characterization by cyclic voltammetry (CV), thus enabling us to conduct simultaneous optical and electrochemical measurements in total internal reflection (TIR) geometry. We have used the system to study biomimetic interfaces created by reconstituting soluble and membrane proteins into artificial bilayer lipid membranes (BLMs) to enable us to mimic many cellular processes in vitro. In particular, we are using the apparatus to study the incorporation of selected proteins into BLMs constituted on gold- and ITO-coated glass surfaces, with the goal of developing biosensors for biomedical applications. In this seminar, the details of the TIRFM apparatus and the development of the optoelectrical capabilities will be presented, along with a discussion of the current collaborative work in our laboratory in support of developing biosensors for a variety of biomedical applications.