Plasmonic smart contact lens based on etalon nanostructure for tear glucose sensing

Smart contact lenses, one of the most advanced wearable platforms, offer a combination of optical and electronic technologies that provide exceptional capabilities in various fields. These lenses are equipped with biosensors, microchips, and sometimes even miniature displays that enable the collection and analysis of biological and environmental data. Smart contact lenses represent a big leap in wearable technology and biosensors, potentially providing a new future for human interaction with the digital world, improving personal health, and promising a hopeful future in vision and wearable technologies. In this study, smart contact lenses based on plasmonic etalon nanostructure have been proposed and fabricated for tear glucose sensing. A cost-effective and simple technique of soft nanolithography has been proposed to fabricate a plasmonic sensor chip on a contact lens, enabling the detection of glucose solutions at different concentrations of 0.15, 1.5, 5, and 10 mM in a phosphate-buffered saline (PBS) solution. The proposed plasmonic etalon-based smart contact lens as a wearable platform exhibits the capacity to sense tear glucose (even at low concentration values) and offers relatively high sensitivity for non-invasive tear glucose sensing applications. The biocompatibility, cost-effectiveness, stability, and simple production of these contact lenses may provide new perspectives on wearable biosensors.