Developing artificial corneal endothelium micro - environment using bioinspired approach

Abstract

In this thesis, micro-environment of healthy corneal endothelium was prepared by mimicking the stiffness and chemistry of underlying layer of endothelium, and inspiring from topography of corneal endothelium. Polyacrylamide (PAAm) hydrogel cell substrates were synthesized with in the stiffness range of Descemet’s membrane’s elastic modulus value of 20-80 kPa. Hexagonal patterns with dimensions 20 m in diameter and 4 m in depth which inspired from mostly hexagonally shaped corneal endothelial cells (CECs) were created on silicon wafer mold via photolithography and transferred to PAAm hydrogels by using soft lithography technique. PAAm hydrogels which have hexagonal patterns were modified with Collagen IV (Col IV), hyaluronic acid (HA) and different amount mixtures of Col IV and HA to mimic corneal endothelium biochemically as well. Chemical modifications were confirmed with Fourier Transform Infrared Spectroscopy (FTIR), Water Contact Angle (WCA) Measurements and Immunofluorescence imaging. After characterization, adhesion, viability and morphology of corneal endothelial cells on these substrates were investigated. The results of cell culture studies indicate that surface topography of substrates enhances cell viability significantly while altering cell morphology. Moreover chemical composition of substrate surface was shown to be an important parameter for growing cell sheets. These results provide a proof of concept for biomimetic and bioinspired strategies for corneal recovery through clinical translations of cell sheet growth approaches.|Keywords : Corneal endothelium, bioinspired, polyacrylamide, hydrogel, topography, micro-environment.