Optimizing the production of alginate microbeads for animal cell aggregate encapsulation using microchannel emulsification
Notice bibliographique
Résumé
Cell encapsulation is a versatile and impactful tool in the biomedical field, with applications in cell therapy, regenerative medicine, drug delivery, and tissue engineering.Microchannel emulsification is a promising technique for water-in-oil droplet production and cell encapsulation.This technique was previously applied to encapsulate mammalian cells using alginate internal gelation biopolymer beads, as well as thermoresponsive chitosan beads.The aim of this work was to apply the technique to encapsulate cellular aggregates including insulin-producing MIN6 cells and human islets of Langerhans.Two main challenges were anticipated: (1) cell viability and death due to acid exposure and (2) increased aggregate settling times which reduces aggregate encapsulation efficiency over time.Aggregate cell viability was a concern since the gelation time and acid concentration was originally designed for beads that were 3 to 4 times larger in diameter than the ones currently produced.The shortening of the bead residence time in acidified oil from 10 minutes to 1 minute made gelled beads with viable cell aggregates.Aggregate sedimentation was an important limiting factor during the process.Beta cell aggregates settled significantly within the alginate solution which resulted in no significant aggregates presence in alginate beads after 15 min in a 60 min production process.To address this challenge, several parameters impacting aggregate settling behaviour were modified: aggregate diameter, dispersed phase density and mechanical stirring.After systematic optimization and analysis, it was shown that the shortening of operating time, and combining optimal conditions had the best impact on increasing cell aggregate encapsulation efficiency.The optimal conditions achieved an average of one cell aggregate per bead.A single encapsulation run at 0.02 mL/min over 60 minutes produced approximately 23,000 beads, with 61% containing at least one cell aggregate.Encapsulated cells remained viable 48 hours post-encapsulation, showing no evidence of dead cores.Overall, this thesis seeks to be the first to successfully encapsulate animal cell aggregates using microchannel emulsification in alginate internal gelation microbeads.I would like the thank my supervisor, Dr. Corinne Hoesli for proposing this project and guiding me these past 2 years.Despite the project having numerous unforeseen difficulties and her rapidly growing lab, she makes time to help me whenever I needed it.Her responses are quick and insightful and always amazing me.Thank you for giving me this opportunity.I would also like to thank Richard Leask for letting me use his biosafety cabinet, fridge, incubator and many more equipment for my experiments.I would also like to thank Richard, Gerald and Austin for repairing the BSC.I would like to thank Sam for machining the pieces for my device modifications and helping with any problems in the designs I made
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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 | 0,001 |
| Méta-épidémiologie (sens strict) | 0,001 | 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 | 0,001 |
| 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 ».