Oxygen Considerations in the Design of Microfluidics for Studying Oxygen Dependent ATP Release from Erythrocytes
Notice bibliographique
Résumé
In recent years, microfluidic devices have become increasingly popular for use in biological studies due to their cost efficiency, low sample consumption rates and length scales that are relevant to cellular biology. They are used in a wide variety of areas including cell signalling. Though microfluidics have proven to be useful in biological settings, it is important to be aware of the O 2 levels to which the living cells are exposed since exposure to unphysiological levels may affect cellular function. Our interests are in the hemoglobin oxygen (O 2 ) saturation dependent ATP release from erythrocytes. Following release, the intravascular ATP then binds to purinergic receptors on the endothelium, causing a conducted signal to upstream arterioles which then vasodilate, increasing flow to the network. This mechanism is believed to be a key player in the local regulation of O 2 supply in the microvasculature. Further, ATP release has been shown to be impaired in multiple cardiovascular diseases including type II diabetes and sepsis, thus understanding this fundamental signalling phenomenon is of paramount importance. In a previous study (Sove PLOS ONE 2013), we designed and computationally modelled an idealized microfluidic system to measure the dynamics of O 2 ‐dependent ATP release from erythrocytes in vitro . The objective of the design was to create a steep O 2 gradient in the channel to cause a rapid change in hemoglobin O 2 saturation and measure the corresponding levels of ATP released from the erythrocytes; this was verified with the model. Due to constraints in the fabrication process, the design was altered to one that could be fabricated using common soft lithography techniques. Early prototypes of this design did not sufficiently desaturate the erythrocytes, motivating the need for a computational model of the O 2 levels in the microfluidic device. In the present study, a set of computational tools were developed to investigate the O 2 levels in microfluidic systems. These tools include methods for generating the multi‐domain geometries of the microfluidic systems in three spatial dimensions, as well as methods for simulating mass transport using a finite element method. The mass transport model includes the O 2 interaction with the hemoglobin in erythrocytes. The computational model confirms that our early prototypes were not sufficiently desaturating the erythrocytes (maximum desaturation < 2%). This has led to the design of a new device which was guided by our computational model while considering fabrication constraints. The computational model indicates that the new prototype will perform 117.8% better at desaturating the erythrocytes compared to the original design. Thus our new prototype can be easily fabricated using common soft lithography techniques and is able to sufficiently decrease erythrocyte hemoglobin O 2 saturation for our needs. In sum, our computational tools have allowed us to investigate our experimental setup in order to improve our design. These tools can also be applied to other microfluidic systems to verify that appropriate levels of O 2 are being supplied. The model can also be used to account for O 2 consumption by living cells (e.g. endothelial cells) governed by Michaelis‐Menton kinetics ensuring they are exposed to the intended O 2 levels. The next stage of this work will validate the computational model by measuring the O 2 saturation in the new prototype. This new device will then be used to measure the dynamics of ATP release in vitro . Support or Funding Information RJ Sove is funded by a NSERC Doctoral Canada Graduate Scholarship and this project is funded by CG Ellis’ NSERC Discovery Grant
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 | 0,001 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,001 | 0,001 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,001 | 0,000 |
| Science ouverte | 0,001 | 0,000 |
| Intégrité de la recherche | 0,001 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,001 | 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 ».