Effect of poly(ethylene glycol) methacrylate on the ophthalmic properties of silicone hydrogel contact lenses

Abstract

In this study, silicone hydrogels were synthesized via the photoinitiated free radical polymerization of 3-(methacryloyloxy)propyltris(trimethylsiloxy) silane (TRIS), 1-vinyl-2-pyrrolidinone (NVP), methacrylic acid (MAA), and poly(ethylene glycol) methacrylate (PEGMA), with ethylene glycol dimethacrylate (EGDMA) as the cross-linker and 2-hydroxy-2-methylbenzene acetone (D-1173) as the photoinitiator. The equilibrium water content (EWC) and oxygen permeability (Dk) of the synthesized silicone hydrogel polymers were linearly proportional to the hydrophilic PEGMA content. The high PEGMA content of the polymers led to a higher EWC, lower Dk, and lower contact angle. The highest Dk value of the soft lens was 73 barrers, which corresponded with the lowest EWC (31 %) value of the hydrogel without PEGMA. The stiffness of the hydrogel decreased with increasing PEGMA content. The silicone hydrogel adsorbed low amounts of lysozymes and human serum albumin (HSA) due to the anti-fouling properties of PEG moiety. In addition, the synthesized silicone hydrogels were non-cytotoxic as determined by an in vitro L929 fibroblast assay. Therefore, the TRIS-NVP-MAA-PEGMA hydrogel can be potentially used as a contact lens material with adjustable EWC, Dk, and low protein adsorption.