Development of Hydrogel Contact lenses Surface-Functionalized with PEG Chains for Protein Adsorption Studies

Purpose : Polyethylene glycols (PEGs) with different molecular weights (MWs) were covalently immobilized onto surface of hydrogel contact lenses. The effect of PEG immobilization on the surface wettability, protein adsorption, and optical transmittance of the resultant hydrogels were investigated, with a particular focus on the MWs of PEGs compared to unmodified control. Methods : PEGs were carboxylated through Jones oxidation, and conjugated onto hydrogel contact lenses. Quantitation of protein deposition onto hydrogel lenses was performed using reverse-phase high-performance liquid chromatography (RP-HPLC) with a calibration curve for protein. Results : The PEG-modified hydrogel lenses exhibited high transparency and improved surface hydrophilicity compared to the untreated hydrogels. According to the results of the protein absorption investigation, lenses based on a longer PEG chain showed lower protein absorption due to higher hydrophilicity. Conclusion : This report describes the synthesis and characterization of a series of hydrogel contact lenses coated with PEG chains. The PEG-modified lenses showed over 90% transmittance and improved surface hydrophilicity. In particular, the amount of protein adsorbed on the longer PEG-coated lenses decreased significantly relative to those of unmodified and shorter PEG-coated hydrogels. The preparation of hydrogels with a PEG-surface may be a new method for the development of ophthalmic biomaterials as well as protein-resistant devices.