Reduction of Physical Strength and Enhancement of Anti-Protein and Anti-Lipid Adsorption Abilities of Contact Lenses by Adding 2-Methacryloyloxyethyl Phosphorylcholine

Biocompatible 2-methacryloyloxyethyl phosphorylcholine (MPC) can enhance the adsorption of water molecules and is therefore used for manufacturing contact lenses. This study investigated the mechanical strength, anti-protein deposition, and anti-lipid adsorption effects of MPC addition to contact lenses. Experimental contact lenses produced by copolymerizing multiple ratios of MPC to 2-hydroxyethyl methacrylate (HEMA) were analyzed. Atomic force microscopy revealed that MPC addition increased surface roughness. The anti-protein deposition and anti-lipid adsorption effects on poly(HEMA-MPC) polymers of various phosphorylcholine quantities were experimentally confirmed. The water content of the contact lenses was proportional to the MPC content in the polymer. The hydrated PC moiety of MPC drastically altered the network of the poly-HEMA polymer by inserting water molecules, which were trapped in the concave region of the surface. MPC addition had negative effects on all examined strength factors because of structural destabilization of the copolymer through water insertion. The anti-deposition effects of MPC were verified by examining the lysozyme and lipid adsorption abilities of the prepared contact lenses. Our results revealed that MPC enhanced interactions of the poly(HEMA-MPC) copolymer with water molecules; these interactions weakened the mechanical strength of the copolymer but markedly improved the anti-adsorption property of the biomolecules. The optimal proportion of HEMA-MPC for contact lenses is in the range 14.9%–28.5%.