Immobilized hyaluronic acid containing model silicone hydrogels reduce protein adsorption

The physical immobilization of hyaluronic acid (HA) as a wetting agent in contact lens applications was investigated using model silicone hydrogels prepared by co-polymerizing methacryloxy propyl tris (trimethylsiloxy) silane (Tris) and hydroxyethylmethacrylate (HEMA). Two different molecular weights of HA were investigated, as well as various Tris/HEMA ratios. Cross-linked HA, while only present in small amounts, increased water uptake and hydrophilicity in the materials containing 10% Tris; however, no changes were observed in the 4% Tris materials. The presence of the HA was further confirmed by increases in glass transition temperature as measured by differential scanning calorimetry. Lysozyme adsorption was dramatically decreased for materials containing cross-linked HA. The incorporation of HA, previously demonstrated to decrease protein adsorption to model conventional hydrogel materials, may have significant potential for improving the wetting and other properties of silicone hydrogel contact lens materials.