Topographic Signals Modulate Cell Growth and Morphology of Retinal Pigment Epithelial Cells In Vitro

Abstract

Abstract: : Purpose:The main objective of this paper is to design, fabricate, and exploit topographically controlled three-dimensional arrays of micropatterned surfaces interfaced to human retinal pigment epithelial cell line (ARPE-19). Methods:Polydimethylsiloxane (PDMS) surfaces are fabricated using the micro-electronic-mechanical systems (MEMS) fabrication techniques. On the test surfaces, the pillar height (5 and 30µm)and pillar diameter (5 and 30µm)are varied. ARPE-19 seeded onto PDMS surfaces coated with fibronectin was used to observe the cell cycle progression, cell adhesion, cell growth, and morphology over a period of several days. Results:Cell cycle progression measured by labeling with 5-bromodeoxyuridine indicated that 5-µm micropatterned surfaces had no significant effect on the DNA synthesis, as compared to flat surfaces. However, high levels of accumulating BrdU indicates that RPE continue to proliferate after several days of culture in 5-µm micropatterned as well as flat substrates. Flat and 5-µm surfaces showed about the same cell attachment, whereas 5-µm surfaces showed significantly lower cell growth than that of flat surfaces. In addition, scanning electron microscopy and immunofluorescence staining showed that ARPE-19 cells attached and formed mesenchymal phenotype on 30-µm PDMS surfaces by clearly expressing the typical mesenchymal marker, fibronectin. Conclusions:Results from these experiments indicate that three-dimensional geometric control of topographic features may provide cues that regulate RPE cell growth and promote epithelial-mesenchymal transformed morphology. The documentation of biological behavior in this study is a conceptual new approach and the combination of topographical cues it may prove to be very useful for the future design of bio-hybrid interface.

Keywords: retinal pigment epithelium • cell adhesions/cell junctions • retinal adhesion