NON-VIRAL GENE DELIVERY WITH pH-SENSITIVE GEMINI NANOPARTICLES: SYNTHESIS OF GEMINI SURFACTANT BUILDING BLOCKS, CHARACTERIZATION AND IN VITRO SCREENING OF TRANSFECTION EFFICIENCY AND TOXICITY
Notice bibliographique
Résumé
Research on self-assembling gemini surfactants and other amphiphiles for potential gene delivery applications in research as well as in clinical practice, and as alternatives to viral gene delivery vectors, is beginning to focus more on 'structure-activity relationships' to address the current low gene delivery efficiencies of amphiphiles.Some underlying structure-activity relations are beginning to emerge.But, as a better understanding of the factors that govern the transfection abilities of amphiphile molecules emerges, development of improved non-viral vectors with clinical potential may also emerge.The research conducted for this thesis was aimed at the design, synthesis and in vitro investigation of gemini surfactants as one of a family of novel amphiphiles being investigated for gene therapeutic applications.The properties of these compounds can be controlled as well as allowed to vary naturally.Gemini surfactant-based gene delivery systems were prepared and characterized for transfer of Luciferase plasmid (pMASIA.Luc) to both COS-7 and PAM 212 cells.Characterization was accomplished using microscopy, dynamic light scattering (DLS) and zeta (ζ) potential analysis.In vitro gene expression and toxicities were evaluated in COS-7 cell and PAM 212 keratinocyte cultures.The level of in vitro transfection in general was found to correlate strongly with the structure of the gemini surfactants.Among the 12-spacer-12 surfactants, incorporation of a pH-sensitive aza (N-CH 3 ) group, which is also steric hindrance-imposing, in the spacer chain yielded increased transfection, particularly for the 12-7N-12 surfactant.In iii comparison, the incorporation of the more pH-sensitive imino (N-H) group in the 12-7NH-12 surfactant yielded the highest increase in transfection among the 12-spacer-12 surfactants.The deleterious effect of steric hindrance due to the aza group is more evident when comparing the transfection efficiency of 12-5N-12 (1 × aza, higher) vs. 12-8N-12 (2 × aza, lower transfection).Another highlighted structural feature is provided by the fact that both the 12-7NH-12 and 12-7N-12 surfactants had higher transfection efficiencies than 12-5N-12 and 12-8N-12 surfactants; the first pair has trimethylene spacing, which constitutes an optimal separation between nitrogen centres, while the second pair has shorter dimethylene spacings.After expanding the structure of surfactants, transfection efficiencies were found to increase in response to increase in hydrocarbon tail length, but were much lower for surfactants with no amino functional groups, those that lacked the optimal trimethylene spacing, or those having both of these limitations in the gemini surfactant spacer.The 18-7NH-18 surfactant had the highest overall transfection in both COS-7 and PAM 212 cells.Gemini surfactant-based gene delivery systems capable of adopting both polymorphic structural phases and which could undergo pH-induced structural transition demonstrated high transfection efficiencies.Gemini surfactants with both characteristics (e.g., 12-7NH-12-based complexes are both polymorphic and pH-sensitive) had higher transfection than gemini surfactants with only one (e.g., 12-3-12-based complexes are only polymorphic).Overall, the m-7NH-m surfactants, the most efficient surfactants studied, had transfection efficiencies similar to that of the commercial Lipofectamine Plus™ reagent and imposed no higher toxicity on cells relative to the less efficient surfactants.Thus, the design of the m-7NH-m surfactants to enhance their transfection abilities also
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 | 0,001 | 0,000 |
| 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 | 0,000 | 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) | 0,000 | 0,000 |
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 ».