Thèse de doctorat : Ingénierie cellulaire et tissulaire : Nancy 1 : 2009. Thèse de doctorat : Ingénierie cellulaire et tissulaire : Université biélorusse de Minsk : 2009. / Thèse soutenue en co-tutelle. Titre provenant de l'écran-titre.

Thesis (M.S.)--Florida State University, 2004. / Advisor: Dr. Michael H. Peters, Florida State University, College of Engineering, Dept. of Chemical Engineering. Title and description from dissertation home page (viewed 6/15/04). Includes bibliographical references.

Dissertation (Ph.D.)--Auburn University, 2009. / Abstract. Includes bibliographic references (p.136-153).

Immunostimulatory oligodeoxynucleotides (ODN) containing unmethylated CpG motifs are powerful stimulators of innate as well as adaptive immune responses, exerting their activity through the triggering of the endosomally localized TLR9 by a poorly understood mechanism. The immunopotency and broad range of activity of CpG ODN makes it a promising immunotherapeutic for the treatment and prevention of cancer and other diseases. However, rapid degradation of ODN by serum nucleases, low levels of accumulation in target tissue and lack of specificity for and poor uptake into target cells following systemic administration pose significant hurdles for the clinical application of CpG ODN. This thesis describes the immunostimulatory properties of CpG ODN encapsulated in liposomal nanoparticles (LN), a delivery system that overcomes many of the problems impeding the clinical development of "free" ODN. In particular, it is shown that LN delivery of CpG ODN specifically targets the ODN for uptake by immune cells in vivo, providing a basis for significantly enhanced immunostimulatory activity, including more potent innate and adaptive immune responses, that ultimately improve anti-tumour efficacy. A particular focus of this thesis concerns previous observations that methylated sequences in ODN (mCpG ODN) are immunologically inert. It is shown that encapsulation of mCpG ODN in LN results in immunostimulatory activity that is equal to or greater than that observed for LN formulations of the equivalent unmethylated form as judged by various immune parameters and anti-tumour efficacy. Further, it is shown that both LN-mCpG ODN and LN-CpG ODN exert their immunostimulatory effects via TLR9 based on preliminary in vitro results and confirmed by studies performed in TLR9 knockout animals. The mechanisms responsible for the differentiation between both CpG ODN and mCpGODN and how encapsulation endows immunostimulatory potential are explored. It is shown that discrimination occurs upstream of TLR9 and that the lack of immunological activity of free mCpG ODN is not due to differences in uptake, trafficking to endosomal compartments or ability to bind to TLR9, when compared with CpG ODN, but rather due to its ability to colocalize with TLR9 in the endosomal compartment. It is proposed that whereas the uptake of free CpG ODN results in the induction of the Src Family Kinase signalling cascade which mediates the migration of TLR9 from the ER to the late endosome, the uptake of free mCpGODN does not. However, it is suggested that encapsulation bypasses the methylation specific recognition of CpG ODN, allowing for the activation of SFK signalling resulting in subsequent co-localization of TLR9 and mCpG ODN in the endosome thus initiating immunostimulatory activity.

No description available.

Amongst the more promising non-viral DNA vehicles are liposomes, with those derived from cationic lipids showing significant potential, despite moderate transfection levels in vivo. This study has investigated the effect of liposome-anchored ionophore crown ethers on lipoplex-mediated gene transfer in vitro and in vivo. Several liposomes were constructed to include the cytofectin 3β[N(N’,N’-dimethylaminopropane)-carbamoyl] cholesterol (Chol-T), the co-lipid dioleoylphosphatidylethanolamine (DOPE), and 5% (mole/mole) of the cholesteryl crown ethers RUI-128 (aza-18-crown-6) or RUI-129 (aza-15-crown-5). Liposome size and lamellarity were established by transmission electron microscopy. All liposome preparations were shown to bind, condense and protect DNA avidly in the respective band shift, ethidium displacement and nuclease protection assays. Lipoplex targeting to hepatocytes may be achieved via the asialoglycoprotein receptor (ASGP-R), which is abundantly expressed on the human hepatoblastoma cell line HepG2. Therefore six additional liposomes were formulated to include 5% (mole/mole) of the cholesteryl galactosyl RUI-90 (Gal) and cholesteryl glucosyl RUI-92 (Glu) ligands. Their hepatotropic gene delivery was examined in the HepG2 cell line using the pCMV-luc plasmid. Transfection studies in the human embryonic kidney cell line HEK293 (ASGP-R-negative) revealed an increase in transgene activity in lipoplexes displaying the RUI-129 cholesteryl derivative. No ionophore-mediated enhancement of transfection activity was observed in HepG2 cells although Chol-T:DOPE, Chol-T:DOPE:RUI-128 and Chol-T:DOPE:RUI-129 liposomes achieved very high transfection levels, exceeding those of their hepatocyte targeted counterparts. Liposome-anchored crown ethers have been shown to potentiate in vitro transfection activity of lipoplexes in the HEK293 cell line. The novel cholesteryl glycosyl derivatives were, however, unable to enhance the targeted entry of lipoplexes into HepG2 cells. The three most effective preparations from in vitro studies were taken forward for in vivo assessment in NMRI mice at the University of the Witwatersrand Molecular Medicine and Haematology unit. Three groups of mice were employed for the evaluation of Chol-T:DOPE, Chol-T:DOPE:RUI-129 and Chol-T:DOPE:RUI-129-Gal lipoplexes with the Psi-CHECK plasmid. Mice treated with hydrodynamic injection and untreated animals made up two control groups. Luciferase activity was determined on examination of the harvested liver homogenates. All liposomes showed modest, but significant transfection activity (p<0.05) and were well tolerated. The assemblies examined therefore warrant further development. / Thesis (M.Sc.)-University of KwaZulu-Natal, Westville, 2010.

Diss. (sammanfattning) Uppsala : Univ., 2003. / Härtill 6 uppsatser.

Thesis (Ph. D.)--Ohio State University, 2005. / Title from first page of PDF file. Document formatted into pages; contains xvi, 110 p.; also includes graphics (some col.) Includes bibliographical references (p. 98-110). Available online via OhioLINK's ETD Center

Thesis (Ph. D.)--University of Oregon, 2002. / Typescript. Includes vita and abstract. Includes bibliographical references (leaves 184-193). Also available for download via the World Wide Web; free to University of Oregon users. Address: http://wwwlib.umi.com/cr/uoregon/fullcit?p3045088.

Polydiacetylenes (PDAs) exhibit a chromatic response to solvents, temperature, strain and other environmental perturbations. When formed in a solid-state polymerization, the backbone of the polymer is planar which provides extended conjugation polymer backbone. However, when an external force is exerted on the backbone, the extended conjugation is interrupted and an optical shift from blue to red is observed. A system using conjugated PDA Nano structures has been developed as a model to study the reversibility in the fluorescence resonance energy transfer (FRET) and electronic absorption of the PDA liposome particles. In the first study, a reversible system composed of PDA and Sulforrhodamine-101 was utilized where PDA and SR -101 act as acceptor and donor respectively. Colorimetric transition from blue to red in PDA liposomes was achieved through heating the conjugated liposomes. In this work, the FRET mechanism was evaluated without violating the role of nature that energy flows "down" hill and that the role of donor and acceptor in FRET are fixed. Reversible interchanging roles of donor and acceptor over many thermo-chromatic cycles in a modified-PDA-SR101 liposomal system were also evaluated. The nanotubes synthesized are thus unique and robust. The characterization studies showed that the nanotubes are both in Nano and micro scale. Thus the self-assembled chemistry using this material would find wide applications in such areas such as sensors, actuators, and computational devices at both micro and nano scale and further studies might offer them as an encapsulation drug delivery vehicle. Both these studies offer a new insight to the unique properties of polymerized PDA liposomes.