Doctor of Philosophy (PhD)
Recent studies have demonstrated the use of nanomaterials such as metallic nanoparticles, liposomes, and polymer microparticles for biomedical applications, encompassing the field of nanomedicine. For developing novel core-shell metallic nanoparticles with controlled surface morphology, the in situ growth dynamics of colloidal silver-gold core-shell (Ag@Au CS) nanoparticles (NPs) in water are monitored in a stepwise synthesis approach using time-dependent second harmonic generation (SHG) and extinction spectroscopy. Transmission electron microscopy images show that the CS NP surface morphology becomes more smooth and uniform as the reaction proceeds, corresponding to lower, stable SHG signals and narrower plasmonic spectra that are compared to finite-difference time-domain theoretical calculations, showing general agreement. In a related project, the origin and mechanism of the photothermal process of gold NPs in water are investigated under different wavelengths and laser powers to determine the photothermal efficiencies using a simplified model based on thermodynamics, Beer’s law, and Mie theory calculations. Additionally, SHG spectroscopy is used to investigate acetaminophen-induced changes on the adsorption and transport properties of malachite green isothiocyanate dye to the surface of 1,2-dioleoyl-sn-glycero-3-phosphocholine liposomes in aqueous colloidal suspension. SHG measurements are also used to investigate the influence of salt concentration on the adsorption properties of malachite green dye to the surface of polystyrene microspheres in aqueous colloidal suspension at room temperature. Overall, the combined approach of synthesis and characterization with linear and nonlinear spectroscopic techniques provide a detailed foundation for controlling complex nanoparticle synthesis and building fundamental understandings for potential drug-delivery applications in nanomedicine technologies.
Dikkumbura, Asela Sampath, "Colloidal Nanomaterial Surface Chemistry and Characterization Studied by Linear and Nonlinear Spectroscopy" (2021). LSU Doctoral Dissertations. 5674.
Haber, Louis H.
Available for download on Saturday, October 26, 2024