Contact lenses are medical devices commonly used to correct refractive errors and to maintain ocular health. Microorganisms such as bacteria that grow on the lens surface cause irritation to the eyes and can even cause loss of vision. In this paper, two different coating strategies are employed to form an efficient antimicrobial coating on contact lenses. In the first method, a presynthesized copolymer of polyethyleneimine-graft-polyethylene glycol methacrylate (PEI-PEGMA) is used and the coated lenses show antimicrobial activity (in vitro) against methicillin-resistant Staphylococcus aureus (MRSA) bacteria with killing efficacy >99.99% and log reduction of 5.1 and proxy host cell viability of 79%. In the second method, commercially available monomers/polymers such as glycidyl methacrylate (GMA), sulfobetaine methacrylate, and polyethyleneimine are used. A typical formulation consisting of 1% GMA shows antibacterial activity against MRSA with killing efficacy >99.99% and log reduction of 6.3. Proxy host cell viability for the coated lenses is found to be 90% indicating that the coating is nontoxic. Antibacterial coating reported here is very effective in killing gram-positive bacteria such as MRSA and S. aureus. The second method using commercially available monomers/polymers involving a simple coating procedure is also easily scalable.
Keywords: antimicrobial; cell viability; coating; contact lenses; polymers.
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