TY - JOUR
T1 - Estimation of the effective intercellular diffusion coefficient in cell monolayers coupled by gap junctions
AU - Olesen, Niels Erik
AU - Hofgaard, Johannes P
AU - von Holstein-Rathlou, Niels-Henrik
AU - Nielsen, Morten Schak
AU - Jacobsen, Jens Christian Brings
N1 - Copyright © 2011 Elsevier B.V. All rights reserved.
PY - 2012/7/16
Y1 - 2012/7/16
N2 - Objective: A recently developed dye-based assay to study gap junction permeability is analysed. The assay is based on electroporation of dye into a large number of connexin 43 expressing cells, grown to confluency on electrically conductive slides. The subsequent intercellular spread of dye to non-electroporated parts of the monolayer enables estimation of the intercellular coupling. So far, the extent of dye spread has been analyzed in qualitative terms only and not in a manner based directly on the physics of the underlying diffusion process. Methods: We apply a continuum approximation assuming that the observed dye spread can be described by Fick's law of diffusion. Deduced from Fick's law, new measures are presented which directly relate the observed spread of dye to the diffusion coefficient. Results: The theoretical framework enables the estimation of an effective diffusion coefficient from Fick's law independently of the specific indicator substance used in the assay. For Lucifer Yellow, diffusion stops within few minutes after the electroporation. Therefore only an order-of-magnitude estimate of the diffusion coefficient can be given for this dye. Conclusion: In terms of the underlying diffusion coefficient, the hitherto used measures give a relatively poor degree of quantification. In contrast, the present methods may yield direct information on the effective intercellular diffusion coefficient and hence provide additional and more precise information as to the permeability modulating effect of various substances.
AB - Objective: A recently developed dye-based assay to study gap junction permeability is analysed. The assay is based on electroporation of dye into a large number of connexin 43 expressing cells, grown to confluency on electrically conductive slides. The subsequent intercellular spread of dye to non-electroporated parts of the monolayer enables estimation of the intercellular coupling. So far, the extent of dye spread has been analyzed in qualitative terms only and not in a manner based directly on the physics of the underlying diffusion process. Methods: We apply a continuum approximation assuming that the observed dye spread can be described by Fick's law of diffusion. Deduced from Fick's law, new measures are presented which directly relate the observed spread of dye to the diffusion coefficient. Results: The theoretical framework enables the estimation of an effective diffusion coefficient from Fick's law independently of the specific indicator substance used in the assay. For Lucifer Yellow, diffusion stops within few minutes after the electroporation. Therefore only an order-of-magnitude estimate of the diffusion coefficient can be given for this dye. Conclusion: In terms of the underlying diffusion coefficient, the hitherto used measures give a relatively poor degree of quantification. In contrast, the present methods may yield direct information on the effective intercellular diffusion coefficient and hence provide additional and more precise information as to the permeability modulating effect of various substances.
U2 - 10.1016/j.ejps.2011.08.015
DO - 10.1016/j.ejps.2011.08.015
M3 - Journal article
C2 - 21888966
SN - 0928-0987
VL - 46
SP - 222
EP - 232
JO - European Journal of Pharmaceutical Sciences
JF - European Journal of Pharmaceutical Sciences
IS - 4
ER -