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Abstract

Bioengineering

Fabrication évolutive d’étirable, Dual Channel, puces microfluidiques orgue

Published: October 20th, 2018

DOI:

10.3791/58151

1Wyss Institute for Biologically Inspired Engineering, Harvard University, 2Apple, Inc, 3Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, 4Vascular Biology Program and Department of Surgery, Boston Children's Hospital and Harvard Medical School
* These authors contributed equally

ERRATUM NOTICE

Important: There has been an erratum issued for this article. Read more …

Un nombre important de composés de plomb échoue dans le pipeline pharmaceutique parce que les études chez l’animal omettent souvent de prévoir les réactions cliniques chez des patients humains. Humaine orgue-on-a-Chip (puce de l’orgue) cell culture Dispositifs microfluidiques, qui fournissent une plate-forme expérimentale in vitro pour évaluer l’efficacité, la toxicité et profils pharmacocinétiques de (PK) chez les humains, peut-être meilleurs prédicteurs de l’efficacité thérapeutique et sécurité dans la clinique par rapport aux études chez l’animal. Ces dispositifs peuvent être utilisés pour modéliser la fonction de n’importe quel type d’orgue et peuvent être assistés connectés en commun microcanaux bordées d’endothélium pour effectuer des études in vitro sur la physiologie humaine ensemble corps-niveau et orgue sans avoir à réaliser des expériences sur les personnes. Ces puces d’orgue se composent de deux canaux microfluidiques perfusé séparés par une membrane élastomère perméable avec organe-spécifiques des cellules parenchymateuses sur un côté et endothélium microvasculaire sur l’autre, qui peut être étiré de façon cyclique à fournir certains organes mécaniques cues (p. ex., respiration des requêtes dans les poumons). Ce protocole détaille la fabrication de canal flexible double, orgue puces par moulage de pièces en 3D imprimé de moules, de combiner plusieurs casting et étapes de post-traitement. Poly poreux (siloxane diméthylique) membranes (PDMS) sont coulés avec micromètre de taille à travers-trous à l’aide de tableaux de pilier de silicium sous compression. Fabrication et assemblage de puces orgue consiste à équipement et des mesures pouvant être mises en œuvre à l’extérieur de la salle blanche traditionnelle. Le présent protocole aux chercheurs accès à la technologie de la puce de l’orgue pour in vitro études niveau des organes et des corps dans la découverte de médicaments, de sécurité et de tests d’efficacité, ainsi que des études mécanistes de processus biologiques fondamentaux.

Erratum

Erratum: Scalable Fabrication of Stretchable, Dual Channel, Microfluidic Organ Chips

An erratum was issued for: Scalable Fabrication of Stretchable, Dual Channel, Microfluidic Organ Chips.  The Representative Results, Discussion, and References sections have been updated.

In the Representative Results section, the legend for Figure 5 has been updated from:

Figure 5: Permeability of inert tracer Cascade Blue through the microporous PDMS membrane. Cascade Blue hydrazide dye in medium was loaded into the top channel of the Organ Chip and perfused at 60 µL/h to measure the flux of the dye across the membrane into the bottom channel containing medium. Empty chips were compared to Gut Chips with Caco2-BBe1 cells in the apical channel and human vascular endothelial cells (HUVEC) in the basal channel cultured for 6 days. Error bars indicate standard error of the mean.

to:

Figure 5: Permeability of inert tracer Cascade Blue through the microporous PDMS membrane. Cascade Blue hydrazide dye in medium was loaded into the top channel of the Organ Chip and perfused at 60 µl/h to measure the flux of the dye across the membrane into the bottom channel containing medium. Empty chips were compared to Gut Chips with Caco2-BBe1 cells in the apical channel and human vascular endothelial cells (HUVEC) in the basal channel cultured for 6 days. The apparent permeability (Papp, cm/s) of the microporous PDMS membrane was determined using the dye concentration in the outlet channels. The gut chip cell layers provide a significantly increased barrier to permeability. Error bars indicate standard error of the mean.

In the Discussion section, the fourth paragraph has been updated from:

Troubleshooting the resulting Organ Chips takes place at two levels: during the fabrication process and during Organ Chip culture. We have developed a visual method for quality assurance (QA) of through-hole formation in the cast membranes that greatly accelerates the production process while improving the quality and reliability of assembled Organ Chips. This QA method allows for process troubleshooting, and we recommend keeping a record of process conditions to enable tracking fabrication problems that may occur during cell culture. During Organ Chip culture, inert tracer dyes are the simplest method of measuring barrier function to troubleshoot the fabrication process and cell culture steps. Lucifer Yellow has been used historically due to its small molecular mass and innate fluorescence, but Cascade Blue offers similar properties with a narrower emission spectrum that is less likely to interfere with downstream assays. Larger molecules, such as poly-ethyleneglycol (PEG)- or dextran-conjugated fluorophores are larger and consequently result in lower permeability overall and lower sensitivity. The apparent permeability (Papp, cm/s) of tracer dyes can be used to determine barrier function properties of organs or tissues (Figure 4). The following equation can be used to calculate Papp between the dosing channel and receiving channel and is derived from equations used primarily for Transwell studies19,20 and corrects for tracer dye loss caused by absorption into PDMS by comparing the two output flows and not relying on mass balance assumptions at the outflow.

Equation 1

to:

Troubleshooting the resulting Organ Chips takes place at two levels: during the fabrication process and during Organ Chip culture. We have developed a visual method for quality assurance (QA) of through-hole formation in the cast membranes that greatly accelerates the production process while improving the quality and reliability of assembled Organ Chips. This QA method allows for process troubleshooting, and we recommend keeping a record of process conditions to enable tracking fabrication problems that may occur during cell culture. During Organ Chip culture, inert tracer dyes are the simplest method of measuring barrier function to troubleshoot the fabrication process and cell culture steps. Lucifer Yellow has been used historically due to its small molecular mass and innate fluorescence, but Cascade Blue offers similar properties with a narrower emission spectrum that is less likely to interfere with downstream assays. Larger molecules, such as poly-ethyleneglycol (PEG)- or dextran-conjugated fluorophores are larger and consequently result in lower permeability overall and lower sensitivity. The apparent permeability (Papp, cm/s) of tracer dyes can be used to determine barrier function properties of organs or tissues (Figure 5). The following equation derived by Tran, et al.19 can be used to calculate Papp between the dosing channel and receiving channel, which partially corrects for tracer dye loss caused by absorption into PDMS by averaging the two output flows and not relying on mass balance assumptions at the outflow.

Equation 1

The References section has been updated from:

  1. Blaser, D.W. Determination of drug absorption parameters in Caco-2 cell monolayers with a mathematical model encompassing passive diffusion, carrier-mediated efflux, non-specific binding and phase II metabolism. at <http://edoc.unibas.ch/655/1/DissB_7998.pdf> (2007).
  2. Hubatsch, I., Ragnarsson, E.G.E., Artursson, P. Determination of drug permeability and prediction of drug absorption in Caco-2 monolayers. Nature Protocols. 2 (9), 2111-2119 (2007).
  3. Henry, O.Y.F. et al. Organs-on-chips with integrated electrodes for trans-epithelial electrical resistance (TEER) measurements of human epithelial barrier function. Lab on a Chip. 17 (13), 2264-2271 (2017).
  4. Maoz, B.M. et al. Organs-on-Chips with combined multi-electrode array and transepithelial electrical resistance measurement capabilities. Lab on a Chip. 17 (13), 2294-2302 (2017).
  5. Benam, K.H. et al. Matched-Comparative Modeling of Normal and Diseased Human Airway Responses Using a Microengineered Breathing Lung Chip. Cell Systems. 3 (5), 456-466.e4 (2016).

to:

  1. Tran, T.T. et al. Exact kinetic analysis of passive transport across a polarized confluent MDCK cell monolayer modeled as a single barrier. Journal of Pharmaceutical Sciences. 93 (8), 2108–2123 (2004).
  2. Henry, O.Y.F. et al. Organs-on-chips with integrated electrodes for trans-epithelial electrical resistance (TEER) measurements of human epithelial barrier function. Lab on a Chip. 17 (13), 2264-2271 (2017).
  3. Maoz, B.M. et al. Organs-on-Chips with combined multi-electrode array and transepithelial electrical resistance measurement capabilities. Lab on a Chip. 17 (13), 2294-2302 (2017).
  4. Benam, K.H. et al. Matched-Comparative Modeling of Normal and Diseased Human Airway Responses Using a Microengineered Breathing Lung Chip. Cell Systems. 3 (5), 456-466.e4 (2016).

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