Date of Award

12-2020

Document Type

Campus Access Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Chemistry/Green Chemistry

First Advisor

Michelle Foster

Second Advisor

Jason Evans

Third Advisor

Daniel Dowling

Abstract

Liquid metal nanoparticles attract great attention due to their unique chemical and physical properties, such as a low melting point and the presence of native oxide skin on its surface. This oxide skin provides novel prospects for synthesizing next generation core shell nanoparticles for applications in catalysis, microelectronics and drug delivery. Herein, change in surface morphology and nanomechanical properties of eutectic Gallium Indium (EGaIn) liquid metal nanoparticles are examined as a function of temperature. At a specific temperature, the particles undergo simultaneous fracturing and healing of the oxide shell due to differences in thermal expansivities of the constituent elements thus leading to rigid and thicker oxide layer. Understanding fundamental surface chemistry of the ligand-nanoparticle interface is crucial for evaluating efficiency of these EGaIn nanoparticles. The effect of aliphatic chain length of the carboxylic acids on colloidal stability and rheological properties of EGaIn nanoparticles are investigated. EGaIn nanoparticles are synthesized coated with aliphatic carboxylic acids of chain length C2-C18. Raman and DRIFT spectroscopies confirm reaction of the ligand with the oxide shell of the EGaIn nanoparticles. A change in particle size distribution as the number of carbon atoms in the carboxylic acid increases is quantified using atomic force microscopy (AFM). AFM F-D measurements are used to measure the stiffness of the carboxylate coated EGaIn nanoparticles and reveal the conformational changes that the hydrocarbon tails undergo with compression. EGaIn nanoparticles are further fabricated to serve as a potent nanocarrier for targeted drug delivery device. A new EGaIn nanoplatform is developed by coating the EGaIn nanoparticles with targeting ligand, hyaluronic acid (HA), and Photosensitizers (PS), light-activatable chemicals that are used for Photodynamic Therapy (PDT). HA improves the biocompatibility of EGaIn nanoparticles and enhances targeting ability to the cancer cells. The nanocarrier is not toxic to cells, in vitro. EGaIn nanoparticles coated with HA and the PS, a benzoporphyrin derivative (BPD) show effective photodynamic efficacy. The methodical approach explored in this dissertation work to understand the gaps in the knowledge of interfacial region near and at the surface of these liquid metal nanoparticles will offer a fertile ground for future development of new materials as cancer therapeutic agents.

Comments

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