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The binding of a drug or other ligand to plasma proteins can effect their absorption, metabolism and excretion which can lead to a change in its toxicity and therapeutic action. Fluorescence is a technique that has been used to study such interactions and has the advantages of extreme sensitivity and specificity. Previously fluorescence has been monitored in the UV /vis range of the spectrum. However, a new development is long wavelength fluorescence (600-1000nm), which has the added benefits of a lower background, decreased scattering, decreased photodecomposition and the availability of inexpensive, solid state, optical components. Certain dyes including polymethines, xanthenes and phenoxazines that fluoresce in the long wavelength region (600-1000nm) of the spectrum were investigated for use as fluorescence probes. Nile Red, a strongly hydrophobic phenoxazine dye, was found to have an emission wavelength and intensity which was strongly dependent on the polarity of its environment. Consequently, it was bound to certain proteins including bovine and human serum albumin, aI-acid glycoprotein and B-lactoglobulin and provided both qualitative and quantitative information on the nature and type of binding site on the protein. It was also used in the study of ligand protein binding interactions in which competition for a binding site on the protein occurs between the probe and other ligands such as drugs or fatty acids. The project also involved a preliminary investigation into a novel double probe technique for the study of drug-protein interactions and the development of a flow injection analysis method involving gradient titration of a drug against a probe:protein system.

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Understanding deformations during interaction of colloidal or nano droplets. has important implications in a wide range of applications such as flotation collection and emulsion stability. The present work is important and necessary because current models are unable to properly describe recent experimental results obtained using the Atomic Force Microscope (AFM) and Surface Force Apparatus (SFA). We revisit and improve on theories involving interacting deformable droplets. A detailed theoretical model of the experiments, which accounts for surface forces, hydrodynamic interactions, droplet deformation and AFM cantilever detection, has been developed. The new feature of the model is the use of matched asymptotic expansions to derive a new boundary condition at constant volume to obtain results that are independent of the size of the computational domain. The AFM experiments provide measurements of dynamical forces between two interacting droplets as well as between a drop and a colloidal particle of micrometre radii in solution when they are driven together and then are retracted from each other. The SFA experiments measure (time dependent) surface profiles of a millimetre size mercury drop interacting with a mica surface. Different configurations have been studied including mechanical and electrical perturbations to a thin film stabilized by double layer repulsion. Interesting experimental features were observed when approaching or retracting the mica from the mercury drop.

Thesis (Ph.D.)--Tufts University, 2001. / Adviser: W. Anthony Mann. Submitted to the Dept. of Physics. Includes bibliographical references (leaves 125-130). Access restricted to members of the Tufts University community. Also available via the World Wide Web;

Thesis (Ph.D.)--University of Delaware, 2007. / Principal faculty advisor: Abraham M. Lenhoff, Dept. of Chemical Engineering, and Eric W. Kaler, College of Engineering . Includes bibliographical references.

Thesis (Ph. D.)--University of Adelaide, Dept. of Physics and Mathematical Physics, 1993. / Copies of author's previously published articles inserted. Includes bibliographical references (leaves 103-108).