Direct Laser Interference Patterning of Graphene in Contact Lenses

This study explores a cost-effective method for creating nanostructures on contact lenses (CLs) as potential wearable sensors. Using direct laser interference patterning, commercially available CLs are coated with graphene ink and ablated with a neodymium-doped yttrium aluminum garnet laser at 30 mJ pulse energy and various tilt angles. The process successfully produces graphene nanostructures on both flat and curved lens surfaces, resulting in a prominent holographic effect. Scanning electron microscopy is used to record groove profiles. Diffraction efficiencies are optimized by varying graphene coating time, achieving a maximum of 0.25%. Contact angle measurements indicate hydrophobicity in the range of 73° to 84.8°. Oxygen permeability, calculated from equilibrium water content measurements, is found to be favorable for corneal health. The Trypan blue assay demonstrates good biocompatibility of the graphene-incorporated lenses. This novel approach offers a promising, commercially viable method for developing CLs that have potential applications as wearable sensors and in ocular diagnostics.