Recently, smart contact lenses with electronic circuits have been proposed for various sensor and display applications where the use of flexible and biologically stable electrode materials is essential. Graphene is an atomically thin carbon material with a two-dimensional hexagonal lattice that shows outstanding electrical and mechanical properties as well as excellent biocompatibility.
In addition, graphene is capable of protecting eyes from electromagnectic (EM) waves that may cause eye diseases such as cataracts. Here, we report a graphene-based highly conducting contact lens platform that reduces the exposure to EM waves and dehydration. The sheet resistance of the graphene on the contact lens is as low as 593 Ω/sq (±9.3%), which persists in an wet environment.
The EM wave shielding function of the graphene-coated contact lens was tested on egg whites exposed to strong EM waves inside a microwave oven. The results show that the EM energy is absorbed by graphene and dissipated in the form of thermal radiation so that the damage on the egg whites can be minimized.
We also demonstrated the enhanced dehydration protection effect of the graphene-coated lens by monitoring the change in water evaporation rate from the vial capped with the contact lens. Thus, we believe that the graphene-coated contact lens would provide a healthcare and bionic platform for wearable technologies in the future.
Researchers at Seoul National University, Graphene Square and Interojo have shown that graphene-coated contact lenses could protect eyes from electromagnetic radiation and dehydration and be used in various healthcare and wearable technologies.
The researchers began by synthesizing a graphene layer on a copper foil using CVD. They then transferred the carbon sheet onto the surface of a contact lens with the help of a polymer layer after etching the copper. “Thanks to its outstanding flexibility, graphene can be coated on the convex lens surface and conform to it,” explains the team.
The team tested the EM wave-shielding properties of the coated lens by testing it out on egg whites exposed to strong EM waves inside a microwave oven. The results showed that the EM energy is absorbed by the graphene layer and dissipated as heat throughout it so that damage to the egg white is minimized.