CATANIONIC SURFACTANT VESICLES: TECHNOLOGY FOR VACCINE DEVELOPMENT AND TARGETED DRUG DELIVERY APPLICATIONS

Catanionic surfactant vesicles have gained attention due to their structural similarities to liposomes and their robust properties in biological media. Catanionic vesicles are formed from oppositely charged surfactants and can be exploited for applications in vaccine production and drug delivery. The focus of my research has been on the preparation, characterization, and application of functionalized catanionic surfactant vesicles. Chapter 2 describes the preparation and characterization of catanionic vesicles containing sodium dodecylbenzenesulfonate (SDBS) and cetyltrimethylammonium tosylate (CTAT). Vesicle solutions were determined to be stable for greater than 6 months, formed vesicles with two populations of 80 and 160 nm, and had a membrane surface charge similar to human cells, -56 mV. Furthermore, vesicles were stable between a pH of 2 and 12, in saline solutions up to 0.6 M NaCl, and after autoclaving. Next, I report the loading of various molecules into the vesicle leaflet and the characterization of the resulting functionalized systems. Hydrophobic molecules were readily incorporated into the hydrophobic region of the leaflet. Lipid conjugates of hydrophilic molecules were anchored in the vesicle bilayer. Chapters 3 and 4 report the loading of biological materials (i.e. liposaccharides and proteins) into catanionic vesicles for the development of bacterial vaccines. Initial studies, discussed in Chapter 3, pertain to the loading of the pure components lipooligosaccharide (LOS) and C12 -Pan DR helper T cell epitope (PADRE) conjugate into catanionic vesicles. A single dose of these vesicles generated a large IgG antibody titer in mice. Next, in Chapter 4, we focus on the extraction of cellular membrane components from cells for their direct incorporation into catanionic vesicles. Vesicles were prepared by adding surfactants in the presence of Neisseria gonorrhoeae cells. Vesicle extracts contained pathogen-derived LOS F62ΔlgtD and a subset of proteins from the outer membrane of the bacterium, including porin and OPA. Lastly, Chapter 5 describes catanionic vesicles in drug delivery. Vesicles were loaded with 88 μg/mL of doxorubicin and shown to retain the drug over 15 days. Doxorubicin loaded into catanionic vesicles were shown to be less toxic as compared to the free drug, IC 50 = 51 μg/mL and 0.16 μg/mL, respectively

Faculty and Administrative Partnerships: Disciplinary Differences in Perceptions of Civic Engagement and Service-Learning at a Large, Research-Extensive University

In recent years, considerable energy has been expended attempting to define, evaluate and promote active learning pedagogies such as civic engagement and service-learning. Yet much of this scholarship treats civic engagement and service-learning at either a macroscopic level (studying an entire university system) or microscopic level (studying a particular course or project). There has been comparably less research examining how different disciplinary cultures influence the conceptualization and implementation of active learning pedagogies within individual institutions. This study draws on quantitative survey methodologies to examine faculty perceptions of civic engagement and service-learning at a major public research university within and across four disciplines: the Humanities, Behavioral and Social Sciences, Science, Technology, Engineering, and Mathematics (STEM), and the Applied Professions. Quantitative results reveal significant variance in disciplinary approaches to civic engagement and service-learning across a variety of measures including advocacy, concerns, and goals for active learning pedagogies. The findings suggest several strategies for recognizing disciplinary differences and encouraging collaboration among faculty and between disciplines on civic engagement and service-learning approaches in higher education

Extraction of Membrane Components from Neisseria gonorrhoeae Using Catanionic Surfactant Vesicles: A New Approach for the Study of Bacterial Surface Molecules

Identification of antigens is important for vaccine production. We tested extraction protocols using cetyltrimethylammonium tosylate (CTAT) and sodium dodecylbenzenesulfonate (SDBS) to formulate surfactant vesicles (SVs) containing components from Neisseria gonorrhoeae. Carbohydrate and protein assays demonstrated that protein and carbohydrates were incorporated into the vesicle leaflet. Depending on the extraction protocol utilized, 100–400 µg of protein/mL of SVs solution was obtained. Gel electrophoresis followed by silver staining demonstrated that SV extracts contained lipooligosaccharide and a subset of bacterial proteins and lipoproteins. Western blotting and mass spectral analysis indicated that the majority of the proteins were derived from the outer membrane. Mass spectrometric and bioinformatics analysis of SVs identified 29 membrane proteins, including porin and opacity-associated protein. Proteins embedded in the SVs leaflet could be degraded by the addition of trypsin or proteinase K. Our data showed that the incorporation of CTAT and SDBS into vesicles eliminated their toxicity as measured by a THP-1 killing assay. Incorporation of gonococcal cell surface components into SVs reduced toxicity as compared to the whole cell extracts, as measured by cytokine induction, while retaining the immunogenicity. This process constitutes a general method for extracting bacterial surface components and identification of antigens that might be included in vaccines.https://doi.org/10.3390/pharmaceutics1209078

Extraction of Membrane Components from Neisseria gonorrhoeae Using Catanionic Surfactant Vesicles: A New Approach for the Study of Bacterial Surface Molecules

Identification of antigens is important for vaccine production. We tested extraction protocols using cetyltrimethylammonium tosylate (CTAT) and sodium dodecylbenzenesulfonate (SDBS) to formulate surfactant vesicles (SVs) containing components from Neisseria gonorrhoeae. Carbohydrate and protein assays demonstrated that protein and carbohydrates were incorporated into the vesicle leaflet. Depending on the extraction protocol utilized, 100–400 µg of protein/mL of SVs solution was obtained. Gel electrophoresis followed by silver staining demonstrated that SV extracts contained lipooligosaccharide and a subset of bacterial proteins and lipoproteins. Western blotting and mass spectral analysis indicated that the majority of the proteins were derived from the outer membrane. Mass spectrometric and bioinformatics analysis of SVs identified 29 membrane proteins, including porin and opacity-associated protein. Proteins embedded in the SVs leaflet could be degraded by the addition of trypsin or proteinase K. Our data showed that the incorporation of CTAT and SDBS into vesicles eliminated their toxicity as measured by a THP-1 killing assay. Incorporation of gonococcal cell surface components into SVs reduced toxicity as compared to the whole cell extracts, as measured by cytokine induction, while retaining the immunogenicity. This process constitutes a general method for extracting bacterial surface components and identification of antigens that might be included in vaccines