Physical Sciences and Mathematics Commons^™

Antimicrobial Strategies For Topical Applications, Kelsey Marie Lopez

LSU Doctoral Dissertations

Bacteria can thrive in diverse environments and are often harmless or beneficial. Bacteria in digestive tracts is one example of beneficial bacteria; however, bacteria can be harmful and when this type proliferates, it can cause infections within hosts. Bacterial infections are easily treated with antibiotics in most cases. However, bacteria are also capable of developing mutations which could cause them to become multi-drug resistant and eventually, “superbugs.” Therefore, the development of novel antimicrobial agents and materials capable of combating drug-resistant bacteria is necessary. Research presented in this dissertation focuses on different strategies for minimizing and preventing topical bacterial infections using …

Quartz Crystal Microbalance Based Sensors For Detection And Discrimination Of Volatile Organic Compounds Using Ionic Materials, Stephanie R. Vaughan

LSU Doctoral Dissertations

Volatile organic compounds (VOCs) are prevalent in everyday life, ranging from household chemicals, naturally occurring scents from common plants and animals, to industrial-scale chemicals. Many of these VOCs are known to cause adverse health and environmental effects and require regulation to prevent pollution. Detecting VOCs plays a critical role in food quality control, environmental quality control, medical diagnostics, and explosives detection. Thus, development of adequate sensing devices for detection and discrimination of VOCs is of great importance. In recent years, use of quartz crystal microbalance (QCM) based sensor arrays for analyses of VOCs has attracted significant interest. Detection of VOCs …

Photo-Physical Properties Of Novel Gumbos For Optoelectronic Applications, Thenahandi Prasanthi Deepthika De Silva

LSU Doctoral Dissertations

Organic Light Emitting Diodes (OLEDs) are predicted to revolutionize next generation consumer electronics by offering many advantageous device characteristics, including low power consumption, low heat dissipation, a tunable and wider color gamut, high resolution and contrast, light weight, flexibility, and semi-transparency. However, a major limiting factor for OLEDs to reach their full potential is that only a few known blue OLED emitters with substantial spectral purity and longevity are available to date. Therefore, focus of this research is on understanding and addressing limitations of OLED emitters, with an emphasis on improving the characteristics of blue emitters.

The work presented in …

Chemotherapeutic Applications Of Rhodamine Based Nanogumbos, Nimisha Bhattarai

LSU Doctoral Dissertations

The work presented in this dissertation employs nanomaterials derived from a group of uniform materials based on organic salts (GUMBOS) for selective chemotherapeutic applications. GUMBOS, similar to ionic liquids, are organic salts consisting of a bulky cationic and anionic moiety. In contrast to ionic liquids, these materials have melting points ranging from 25–250 °C, making them solid phase at room temperature. Similar to ionic liquids, GUMBOS display tunable properties, such as hydrophobicity and solubility, through counter ion variation. These tunable properties provide a variety of applications for these GUMBOS, including selective chemotherapeutics applications. The …

Biomedical Applications Of Hydrogels And Gumbos, Kelsey Elizabeth Mcneel

LSU Doctoral Dissertations

Sodium deoxycholate (NaDC) is a small bile salt that was used in this dissertation to produce gelation of tris(hydroxymethyl)amino-methane (TRIS) solutions above, below, and near the pKa of NaDC. These solutions respectively yielded a neutral gelator, a charged gelator, and a mixture of each. Impacts of ionic interactions on gel formation were studied in detail and showed that pH can be used to modify many hydrogel properties including sol-gel temperature, crystallinity, and mechanical strength. It was also observed that pH modification of the hydrogels affected nanoparticle formation. Nanoparticles derived from a Group of Uniform Materials Based on Organic Salts (nanoGUMBOS), …

Design And Application Of Task-Specific Organic Salts For Chemical And Biochemical Sensing, Waduge Indika Subodha Galpothdeniya

LSU Doctoral Dissertations

There is an increasing demand for development of new sensors and sensor strategies for accurate detection and discrimination of various analytes. In this regard, colorimetric and fluorometric sensor approaches have attracted considerable attention, primarily because they represent facile and inexpensive analytical tools. In this dissertation, I discuss the design and application of sensors and sensor arrays using task specific organic salts: ionic liquids (ILs) and a group of uniform materials based on organic salts (GUMBOS). As compared to typical ionic compounds, these two classes of organic salts exhibit relatively lower melting points due to bulky organic cations and/or anions. Interestingly, …

Gumbos As Matrices For Matrix-Assisted Laser Desorption Ionization Time Of Flight Mass Spectrometry, Hashim Abdullah Al Ghafly

LSU Doctoral Dissertations

This work involves the investigation of a group of uniform materials based on organic salts (GUMBOS) as matrices for matrix assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF) for analysis of hydrophobic biomolecules. GUMBOS are new class of materials that show great promise as MALDI matrices because they are able to form a thin-layer on the MS target, thereby enhancing the sample homogeneity, signal intensity, and shot-to-shot reproducibility. The detection of hydrophobic peptides using MALDI-TOF MS remains a challenge because the majority of matrices utilized are hydrophilic thereby exhibiting low affinity for hydrophobic molecules. To address this, I …

Synthetic Routes To Therapeutic Agents Via Masked Functionalities: From Orthogonal Peptide Crosslink To Photothermal Cancer Prodrug, Chyree Shantel Batton

LSU Doctoral Dissertations

The theonellamides are a family of compounds distinguished by their crosslinking ô-histidinoalanine (ô-HAL) residue. Part one of this dissertation details the synthesis of an orthogonally protected ô-HAL building block that will be incorporated into a total synthesis of theonellamide C. Selective deprotection of each amine and acid of this orthogonally protected building block is also demonstrated. Various reaction partners for the assembly of ô-histidinoalanine were explored. One approach involved the coupling of N-Fmoc-â-iodoalanine benzyl ester and (Nðim)-blocked histidine nucleophiles including a fused bicyclic urea and a Boc-His(Nð-Pac)-OMe. While the imidazolium salts were identified by mass spectrometry, elimination of the iodide …

Studies Of Core-Shell Nanogumbos And Liposomal Ionogels, Ashleigh Renee' Wright

LSU Doctoral Dissertations

The work presented in this dissertation is a description of novel core-shell nanomaterials derived from a group of uniform materials based on organic salts (GUMBOS) and the synthesis and characterizations of novel liposomal ionogels (LIGs). These GUMBOS are an extension of ionic liquids (ILs) which are organic salts with melting points between 25 °C and 100 °C. Ionic liquids have high thermal stability, low vapor pressure, and tunable physiochemical and functional properties. All of the properties of ILs are controlled by the chosen cation and anion pair. Similarly to ILs, GUMBOS possess the same qualities; however, they have melting points …

Chemical And Biological Evaluation Of Antibiotic-Based Ionic Liquids And Gumbos Against Pathogenic Bacteria, Marsha Rae Cole

LSU Doctoral Dissertations

The research presented in this dissertation explores a novel pragmatic therapeutic approach for control, prevention, and treatment of infectious disease using Active-Pharmaceutical Ingredient-based Ionic Liquids (API-ILs) and Groups of Uniform Materials Based on Organic Salts (GUMBOS). Accordingly, several antiseptic- and antibiotic-based API-ILs and GUMBOS were synthesized and characterized using a combination of analytical and microbiological techniques. Overall, this research presents an advanced alternative to combination antibiotic therapy by using a novel group of ionic antimicrobial materials that have controlled pharmacokinetics, improved bioavailabilities, reduced toxicities, multi-modal properties, and potent antimicrobial spectrum of activity as a viable alternative to combating bacterial infections. …

Task Specific Ionic Liquids For Enantiomeric Recognition And Nanomaterials For Biomedical Imaging, David Kipkogei Bwambok

LSU Doctoral Dissertations

Ionic liquids (ILs) are organic salts that melt at or below 100°C. Interest in ILs continues to grow due to their unique properties such as lack of measurable vapor pressure, high thermal stability, tunability and recyclability. The first part of this dissertation explores the use of chiral ionic liquids (CILs) for enantiomeric recognition of chiral analytes using fluorescence spectroscopy. Chiral analyses continue to be a subject of considerable interest primarily as a result of legislation introduced by the Food and Drug Administration. This has led to an increased need for suitable chiral selectors and methods to verify the enantiomeric forms …