Notice bibliographique
Résumé
This thesis is focused on characterizing two lipid-based gene delivery systems: plasmid DNA-cationic lipid "complexes" and stabilized plasmid-lipid particles (SPLP). Complexes have utility for gene transfer in vitro whereas SPLP are designed for systemic gene therapy applications in vivo. In Chapter 2, the structural and fusogenic properties of complexes formed by mixing pCMV5 plasmid DNA with large unilamellar vesicles (LUVs) composed of the cationic lipid N-[2,3-(dioleyloxy)propyl]- N,N,N-trimethylammonium chloride (DOTMA) and l,2-dioleoyl-3-phosphatidylethanolamine (DOPE) or l,2-dioleoyl-3- phosphatidylcholine (DOPC) are examined and correlated with transfection potency. It is shown, employing lipid mixing fusion assays, that pCMV5 plasmid strongly promotes fusion between these cationic vesicles. Freeze fracture electron microscopy studies demonstrate association of cationic vesicles to form clusters at low pCMV5 content, whereas macroscopic fused aggregates can be observed at higher plasmid levels. ³¹P NMR studies on the fused DNA-DOTMA/DOPE (1:1) complexes obtained at high plasmid levels (charge ratio 1.0) reveal narrow "isotropic" ³¹P NMR resonances, whereas the corresponding DOPC containing systems exhibit much broader "bilayer" ³¹P NMR spectra. In agreement with previous studies, the transfection potency of the DOPE containing systems is dramatically higher than for the DOPC containing complexes, indicating a correlation between transfection potential and the motional properties of endogenous lipids. It is suggested that the ³¹P NMR characteristics of complexes lipid structures, which may play a direct role in the fusion or membrane destabilization events vital to transfection. In Chapter 3, the influence of variations in the lipid component of SPLP on plasmid trapping and transfection potency in vitro are characterized. It is shown that SPLP formed with different monovalent cationic lipids exhibit similar plasmid entrapment properties but different transfection potencies. The poly(ethylene glycol) (PEG) density in SPLP can substantially influence both SPLP formation and transfection. By decreasing the length of the fatty acyl component of the PEG-ceramide anchor from 20 to 14 to 8 carbons, or by using smaller PEG chains (PEG₇₅₀, PEG₂₀₀₀ as compared with PEG₅₀₀₀), higher transfection levels were observed, consistent with a requirement for PEG removal in order for efficient transfection to occur. Further, it is shown that the primary factor limiting the transfection potency of SPLP is association and uptake into target cells. The final set of experiments in Chapter 4 was focused on characterizing the influence of the plasmid component in the formation of SPLP. It is shown that encapsulation efficiencies remain at 50 % or higher for (initial) plasmid-to-lipid ratios of up to 70 μg/μmol, allowing the proportion of lipid in empty vesicles following detergent dialysis to be significantly reduced compared to previous protocols. In addition, it is shown that the encapsulation efficiency is sensitive to the conformation of the plasmid employed, where higher encapsulation is observed for linearized plasmid as compared to plasmid in supercoiled or relaxed circular conformations. However, lower transfection potency for linearized plasmid was observed in SPLP and plasmid DNA-cationic lipid complexes.
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,001 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,001 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,002 | 0,001 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».