Construction Of Diblock Copolymer Coatings On Contact Lenses Surface For Improving Biocompatibility

Contact lenses, whilst being a prevailing form of vision correction, are attracting more patients with myopia. When contact lenses seats in eyes, adverse reactions such as keratitis and corneal ulcer would occur and limit the further popularization of contact lenses.Zwitterionic polymers have anion and cation groups simultaneously, which make them forming hydration layer on the surface and render them unique biocompatibility, such as resisting nonspecific protein adsorption and bacterial adhesion. Surface modification with biocompatible zwitterionic polymer to improve the anti-biofouling properties of contact lenses is an effective way to reduce the microbially-driven adverse responses.In this study, three different compositions copolymers synthesis with 3-trimethoxysilyl-propyl-methacrylate (MPS) and 2-methacryloyloxyethyl phosphorrylcholine (MPC) using CuBr/bi-pyridine catalytic system via Atom Transfer Radical Polymerization (ATRP) methods. Copolymers structures have been identified by 1-NMR and FTIR. In addition, the mean diameter of the three copolymer particles in ethanol solution was about 25-30 nm measured by Dynamic Light Scattering (DLS).After a convenient "one-step" reaction under triethylamine catalyst, contact lenses were modified by these copolymer solutions to construct effective bio-interface. XPS element analysis, equilibrium moisture content (EWC) and water contact angle measurement made it sure that the copolymer was successfully grafted from contact lenses and the zwitterionic polymer modified surface showed improved water affinity. The modified contact lenses biocompatible property was also confirmed by protein adsorption measurement and bacterial-adhesion test. Among different series, contact lenses with copolymer (5:30) modification presented the best effect, as the amounts of adsorbed BSA were reduced to 36% and AFT were reduced to 46% of that on pristine contact lenses. Furthermore, the initial adhesion of the tested bacteria can be almost suppressed, as the amounts of adsorbed staphylococcus aureus were reduced to 27% of that on pristine contact lenses.The grafting techniques to construct MPC polymer onto contact lenses surface that have been presented in our work have obvious advantages:(1) PMPS-b-PMPC can be applicable to surface modification for majority currently commercially available lens, while they can react easily with hydroxyl groups on contact lenses surface under moderate environment by convenience "one-step" method, as will not affect the basic properties of contact lenses.(2) Contact lenses with PMPS-b-PMPC copolymer modification presented excellent biocompatibility and enhancement of comfort.(3) The anti-biofouling contact lenses provide a convenient and feasible method to solve the microbially-driven adverse responses of contact lenses.