Fig. 1.

Development and characterization of the hiPSC-RPE model on ECIS microelectrodes. (a) Patient's fibroblasts were expanded and reprogrammed with Yamanaka factors Klf4, Oct3/4, Sox2, c-Myc to a pluripotent state before being differentiated to RPE. Cells were plated (Day 0) on ECIS microarrays before being allowed to mature for an additional 3 weeks period. (b) Timeline protocol: Cells were cultured with a density of 100,000 cells/cm². Culturing medium was switched from RDM 10% FCS to RDM 2% FCS on Day 2 of culture, and then to RDM no serum on Day 6. Medium was changed every other day for 25 days until RPE maturation was obtained. (c) The complex impedance was monitored in real-time throughout RPE maturation and is displayed as the resistance at 4 kHz. It showed an increase with cell spreading and maturation followed by a decrease reflecting changes in cell morphology and size. After 25 days, an automated electrical wound healing assay was performed and subsequent cell migration associated with healing phase was monitored. (d) Immunostaining showing the expression of the transmembrane RPE specific protein Bestrophin(red), Ezrin (green) and DAPI (blue) illustrated markers of mature RPE. (e) RT-PCR revealed that both case and control hiPSC-RPE lines expressed global epithelial and RPE specific markers.