A high-density PEG interfacial layer alters the response to an EGF tethered polydimethylsiloxane surface

Abstract

Previously, epidermal growth factor (EGF)-modified surfaces have shown promise in supporting cellular growth and adhesion on synthetic polymeric substrates. Surfaces prepared using a novel modification technique were investigated in the current work for their ability to support corneal epithelialization, important to the integration of a synthetic artificial cornea. EGF could be tethered to PDMS surfaces via a high-density, hetero-bifunctional PEG-NSC linking layer with a tunable surface concentration of up to 300 ng/cm(2). Only a small fraction of the EGF on these surfaces could be removed with SDS rinsing, indicative of covalent tethering. Studies with human corneal epithelial cells suggest a relatively linear increase in the number of corneal epithelial cells with increasing EGF concentration at all times. However, confluence was not achieved at any time point. It is believed that the presence of the non-adsorbent PEG layer, useful for preventing non-specific adsorption of proteins, may limit the cellular response by minimizing the adsorption of adhesion molecules. The effects of the EGF alone are clearly not sufficient to result in epithelialization of an artificial cornea surface. Altering both the adhesion and growth of corneal epithelial cells in a controlled manner may be necessary for epithelialization of an artificial cornea.