Ink based graphene integration into commercial contact lenses.

Introducing multiple functionalities to contact lenses (CLs) are achieved by additives such as nanomaterials, pigments, and dyes. CLs with graphene have been used in electromagnetic interference (EMI) shielding, drug delivery and sensing. Generally, CVD graphene or graphene nanocomposites are used during the manufacturing stage of CLs. In this work, we incorporate graphene into commercial CLs through three post processing techniques: the breath in - breath out (BIBO) technique, immersion of CLs in graphene ink, and 3D printing of graphene hydrogel composite. Graphene ink was used as the aqueous solution in BIBO cycles. The BIBO cycles were repeated to obtain the necessary attachment without losing transparency. In the immersion technique, immersion time controlled the concentration of graphene. In the third method, graphene ink was dispersed in hydroxyethyl methacrylate (HEMA) resin to 3D print patterns onto the CLs. Scanning Electron Microscopy (SEM) was used to observe graphene dispersion within CLs. The UV-Vis spectroscopy of the CLs indicated steady absorption throughout the visible region as a tinting additive, suggesting uses such as broad-spectrum absorbers. These methods could be used to quickly synthesize large amount of functionalized CLs for different applications. The lenses exhibited both anti-bacterial and exceptional biocompatibility properties.