Date of Award

12-31-2025

Document Type

Campus Access Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Chemistry/Physical/Analytical Chemistry

First Advisor

Michelle Foster

Second Advisor

Neil Reilly

Abstract

Liquid metal nanoparticles have emerged as a new class of functional nanomaterials offering a combination of metallic conductivity, fluidity, and surface reactivity. Among them, eutectic gallium–indium (EGaIn) nanoparticles are particularly attractive due to their liquid‐core and oxide‐shell structure, which permits surface modification and integration with organic ligands. The thin gallium oxide shell formed spontaneously on EGaIn serves as a versatile platform for chemical anchoring, enabling the construction of hybrid nanostructures for biomedical applications, especially drug delivery. This dissertation explores how the chemical nature of β-cyclodextrin (β-CD) derivatives, differing in their anchoring functionalities, governs the interfacial chemistry, structural properties, and host-guest behavior of EGaIn nanoparticles.

To bridge molecular inclusion chemistry and nanoparticle surface engineering, β-CD derivatives bearing amino, phosphate, carboxylate, and thiol groups were employed to functionalize EGaIn nanoparticles. The systematic comparison revealed how each anchoring group uniquely influences particle morphology, oxide‐layer structure, and mechanical rigidity. These nanoparticles were further evaluated for their ability to encapsulate a model hydrophobic guest, Coumarin 460, revealing that variations in loading efficiencies are intrinsically linked to the inclusion strength and accessibility of the β-CD cavity. Complementary spectroscopic investigations of the free cyclodextrin derivatives established the mechanistic basis for inclusion—deep inclusion for carboxylate β-CD, partial inclusion for phosphorylated β-CD, weak interaction for aminated β-CD, and external association for thiolate β-CD.

Through integrating insights from both nanoscale and molecular analyses, this work demonstrates how anchoring group chemistry simultaneously controls the inorganic–organic interface and the molecular recognition ability of the coating. Carboxylate β-cyclodextrin achieves the best compromise, forming EGaIn nanoparticles that are morphologically stable, mechanically robust, and capable of deep molecular encapsulation. Amino β-cyclodextrin provides structural stability but limited functionality, phosphate anchoring offers strong attachment but partial accessibility, and thiol anchoring grants transient binding unsuitable for aqueous stability.

Overall, this dissertation establishes a unifying framework that connects coordination chemistry, oxide layer structure, and host–guest interactions in liquid metal hybrid nanoparticles. The findings not only elucidate how functional group chemistry shapes both stability and inclusion capability but also pave the way for designing tunable, biocompatible EGaIn-based nanoplatforms for future applications in targeted and responsive drug delivery.

Comments

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