Electrohydrodynamic Jet-Printed Ultrathin Polycaprolactone Scaffolds Mimicking Bruch's Membrane for Retinal Pigment Epithelial Tissue Engineering

Age-related macular degeneration (AMD) is the leading cause of visual loss and affects millions of people worldwide. Dysfunction of the retinal pigment epithelium (RPE) is associated with the pathogenesis of AMD. The purpose of this work is to build and evaluate the performance of ultrathin scaffolds with an electrohydrodynamic jet (EHDJ) printing method for RPE cell culture. We printed two types of ultrathin (around 7 mu m) polycaprolactone scaffolds with 20 mu m and 50 mu m pores, which possess mechanical properties resembling that of native human Bruch's membrane and are biodegradable. Light microscopy and cell proliferation assay showed that adult human retinal pigment epithelial (ARPE-19) cells adhered and proliferated to form a monolayer on the scaffolds. The progress of culture matured on the scaffolds was demonstrated by immunofluorescence (actin, ZO-1, and Na+/K+-ATPase) and Western blot analysis of the respective proteins. The RPE cells cultured on EHDJ-printed scaffolds with 20 mu m pores presented higher permeability, higher transepithelial potential difference, and higher expression level of Na+/K+-ATPase than those cultured on Transwell inserts. These findings suggest that the EHDJ printing can fabricate scaffolds that mimic Bruch's membrane by promoting maturation of RPE cells to form a polarized and functional monolayered epithelium with potential as an in vitro model for studying retinal diseases and treatment methods.