Graduation Year

2007

Document Type

Dissertation

Degree

Ph.D.

Degree Granting Department

Chemical Engineering

Major Professor

Michael D. VanAuker, Ph.D.

Keywords

Drug delivery, Niosomes, Vesicles, Immunotargeting, Atherosclerosis

Abstract

Cardiovascular disease (CVD) and particularly atherosclerosis is a leading cause of morbidity in the developed world. Atherosclerosis and the rupture of vulnerable atherosclerotic plaque cause 70% of deaths from CVD. The progression of atherosclerosis has been identified as a pathological inflammatory process. Targeting atherosclerotic drug therapies to inflammatory markers has emerged as an important and growing research area. The adhesion molecule CD44 has been implicated in the onset and build-up of atherosclerotic lesions throughout the course of development. The research in this dissertation is aimed at targeting anti-inflammatory therapy to activated vascular endothelium with directed with an anti-CD44 antibody, IM7, conjugated to a non ionic surfactant vesicle (niosome) drug carrier. The IM7 conjugated immunoniosome has been shown to bind to endothelial and synovial lining cells in vitro.

The preliminary research is involved with the development of the drug delivery vesicle, and the antibody linkage chemistry, along with an analysis of vesicle characteristics and stability. A novel linking chemistry using polyoxyethylene sorbitan monostearate and cyanuric chloride allows antibodies to be conjugated to vesicle surface polymer groups without prior derivatization. Subsequent research tested the resulting 'immunoniosome's' ability to bind to target antigens with selectivity and specificity. Bovine aortic endothelial cells activated with cytokines provide a model of inflammation. Analysis of binding was done through fluorescent and scanning electron microscopy. In vivo uptake of vesicles at sites of inflammation is size dependent. In order to overcome this barrier to uptake, niosome suspensions were thermally extruded to create uniform 200 nm vesicles.

Further analysis of the efficacy of the system looked at live cell uptake of the immunoniosomes measured by confocal and transmission electron microscopy. Preparation for in vivo murine studies required that the antibody component was modified to counteract the immune response. Finally, the conjugation of antibody fragments to niosomes and the binding and uptake of the vesicles in a live endothelial cell model is evaluated. A viable drug delivery particle showing binding and cellular uptake capabilities in inflammatory cells was produced by this research using a novel surfactant-antibody linker.

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