(347a) Characterizing Human Airway Transepithelial Ion Transport By Organic Electrochemical Transistor Array

Organic electrochemical transistor (OECT) offers attractive characteristics suitable for measuring ion flows at biological-electronic interfaces. Recent examples for OECTs include cell biosensors to monitor cells’ detachment^[1] and epithelial tissue’ integrity^[2]. In this work, we report, to our knowledge, the first study of monitoring dynamics of transepithelial ion transport in human airway epithelial cells on an integrated OECT array.

For a proof of concept study, an OECT array consisting of 32 micro-OECTs was fabricated on a glass substrate. Conducting polymer, poly(3,4-ethylenedioxythiophene): poly(styrene sulfonic acid) (PEDOT:PSS), with good biocompatibility was used as the active layer where  a direct contact was made with the basal laminar layer of epithelial cells. Selective patterned gold layers were served as source, drain and interconnect. Human airway epithelial Calu-3 cells were directly cultured on the OECT array surface. These cells express abundant cystic fibrosis transmembrane conductance regulator (CFTR) chloride channels in the apical membrane. The activation of CFTR channels results in a transepithelial chloride secretion followed by sodium flow through tight junctions because of electrical attraction, thereby a sodium concentration decrease in the intercellular space at the basolateral side. By taking advantage of the cation-sensitive property of OECT^[3], transepithelial ion flows induced by CFTR channel opening are then adequately reflected by a change of channel current or effective gate voltage of OECT.

Using this approach, this integrated array platform consisting of epithelial cells on OECT has shown a very sensitive dose-response relation upon the addition of forskolin, a classical CFTR agonist. Moreover, the OECT device shown in this study exhibits good transfer characteristics and could be operated at very low voltage. This OECT-based platform has the potential to study ion transport in other physiological processes and can be used as drug testing platform to evaluate drug’s effectiveness on the ion channel related diseases.

References:

[1] P. Lin, F. Yan, J. Yu, H. L. Chan, M. Yang, Adv. Mater. 2010, 22, 3655.

[2] L. H. Jimison, S. A. Tria, D. Khodagholy, M. Gurfinkel, E. Lanzarini, A. Hama, G. G. Malliaras, R. M. Owens, Adv. Mater. 2012, 24, 5919.

[3] P. Lin, F. Yan, H. L. Chan, ACS Appl. Mater. Iinterfaces. 2010, 2, 1637.