Electrodeposition induced covalent cross-linking of chitosan for electrofabrication of hydrogel contact lenses.

To meet the requirement of personalization, there is an urgent need to develop a simple, efficient and versatile manufacturing method for customized contact lens manufabrication. Here, we report a novel electrofabrication methodology (i.e., electrodeposition) for the fabrication of hydrogel contact lenses, which can induce covalent cross-linking between chitosan and epichlorohydrin simultaneously. The transmittance and toughness of hydrogels are improved by electrochemical cross-linking without affecting their oxygen permeability. Furthermore, the geometry of the chitosan based hydrogel contact lenses can be customized simply by the electrode template, and its characteristics can be regulated by electrical signals and electrochemical cross-linking. The electrodeposited hydrogel contact lenses have good optical properties, mechanical properties and biocompatibility, and their anti-adhesion properties to Staphylococcus aureus are close to commercial contact lenses. This work reveals the mechanism of electrochemical cross-linking between chitosan and epichlorohydrin and provides an alternative method for contact lens fabrication.