IONIC LIQUIDS AND GUMBOS FOR BIOMEDICAL AND SENSING APPLICATIONS

Abstract

This dissertation is a synopsis of advancements in the field of ionic liquids and a group of uniform materials based on organic salts (GUMBOS) in biomedical applications, especially with regard to cancer research. The toxicity of chemotherapeutic agents to normal tissues and drug resistance are a major concern in cancer treatment. In this dissertation, GUMBOS and nanoGUMBOS as well as ionic liquids and nanodroplets are explored as possible chemotherapeutic agents with minimal toxicity to normal cells. In the first part of my dissertation, exploitation of ionic liquid chemistry to modulate toxicity of rhodamine 6G is reported. Rhodamine 6G-based GUMBOS with varying counter- anions that are stable under physiological conditions, display excellent fluorescence photostability, and more importantly have tunable chemotherapeutic properties were synthesized. In vitro studies indicate that the hydrophobic compounds of this series allow production of nanoGUMBOS which are non-toxic to normal cells and toxic to cancer cells. Furthermore, the anions, in combination with cations such as sodium, were observed to be non-toxic to both normal and cancer cells. Thus, we demonstrate that both the cation and anion play an extremely important and cooperative role in the anticancer properties of these compounds. In the second part, the concept of multifunctional nanoparticles is introduced and exploited for theranostic applications. Nanoparticles possessing multiple properties such as luminescence, magnetism, and cancer targeting, were synthesized and explored for use in cancer therapy. In this regard, it is demonstrated that these nanoparticles can not only be used in diagnostics and as drug delivery agents, but also as active pharmacophores. Finally, the third part of this dissertation is a report of novel ionic liquid based pH sensitive colorimetric nanosensors based on phosphonium and fluorescein. The pH dependent size changes in the nanodroplets are demonstrated and potential applications in detecting acidic environment and anticancer activity are investigated.