Japanese Researchers Develop Smarter, Safer Contact Lenses

Lenses for the digital age.

Waseda University researchers have developed MXene-coated contact lenses that address concerns about prolonged exposure to electromagnetic radiation from wireless devices. The lenses also maintain hydration and high optical clarity.

The MXene-coated contacts pave the way for safer, next-generation eyewear technologies in healthcare and other applications.

With recent advancements in technology, the Internet of Things and wireless devices are in high demand. However, these innovations also raise concerns about prolonged exposure to electromagnetic radiation (EMR), which may pose potential risks to eye health. MXenes, a class of two-dimensional transition metal carbides/nitrides, have shown promise in shielding against EMR but their poor adhesion and susceptibility to oxidation have limited their applications.

In a recent breakthrough, researchers led by Professor Takeo Miyake from the Graduate School of Information Production and Systems, Waseda University, Japan, have developed stable MXene-coated contact lenses with improved optical and EMR shielding properties. The team’s fabrication method ensures optimum adhesion and prevents oxidation of the MXene coating, overcoming previous limitations.

The study was a collaborative effort between Waseda University, Kyoto University, and Yamaguchi University Hospital, bringing together expertise in nanofabrication, two-dimensional materials, and ophthalmology to ensure eye safety. The findings were published in the journal Small Science on June 4. The research was coauthored by Dr. Lunjie Hu from the Graduate School of Information Production and Systems, Waseda University; Associate Professor Jun Hirotani from Kyoto University; Professor Kazuhiro Kimura from Yamaguchi University Hospital; Assistant Professor Atsushige Ashimori from Yamaguchi University Hospital; and Assistant Professor Saman Azhari from the Graduate School of Information Production and Systems, Waseda University.

“Smart contact lenses with built-in electronic components are getting a lot of attention as the next big thing in wearable devices. For the first time, though, this means we’ll be placing wireless circuit lenses directly on our corneas, exposing them to electromagnetic waves around the clock. Inspired by breakthroughs in 2D materials and device fabrication technologies, we came up with highly functional protective contact lenses,” Miyake said.

To fabricate these highly functional contact lenses, the research team started by preparing dispersions of MXene, which were vacuum filtered with mixed cellulose ester (MCE) membranes to produce MXene-based films. The films were then coated onto commercial soft contact lenses through a wet transfer approach using acetone. The prepared lenses were then analyzed extensively for physical properties, conductivity, and safety. “We chose a wet-transfer method for the effortless attachment of MXene nanosheets to the unconventionally shaped surface of soft contact lenses, which ensures scalability,” Miyake added.

The fabricated contact lenses showed promising results with more than 80% visible light transmission, high conductivity, dehydration protection, and high biocompatibility with more than 90% cell viability. The deposited MXene layers showed variable thickness based on concentrations of the dispersions, and the adhesive properties of the dissolved MCE membrane ensured optimum MXene attachment. Additionally, the MCE layer also protected the MXene from oxidizing.

“Our research can have a multifaceted impact. First, the stable and effortless coating of MXene nanosheets via wet transfer broadens the possibilities for commercial applications,” Miyake stated. “Secondly, our method is simple yet effective in preventing MXene oxidation, turning a commonly overlooked challenge—MXene oxidation—into a resolved obstacle.”

To assess electromagnetic shielding, the MXene-coated lenses were tested on porcine eyes exposed to microwave heating and thermal imaging. The lenses exhibited a rapid temperature rise, indicating strong EMR absorption and dissipation, which prevented direct heating of the eyes. When exposed to high-frequency microwaves, MXene effectively absorbed electromagnetic energy and released it as thermal radiation, thereby protecting the porcine eyes from direct heating.

Furthermore, the researchers confirmed a robust 93% electromagnetic shielding efficiency, representing the highest reported specific shielding effectiveness for biocompatible materials at the same thickness level, offering substantial protection against high-frequency radiation. The lenses demonstrated strong protection against high-frequency EMR, ensuring optimal eye health.

With high electromagnetic protection and reliable properties, this breakthrough in smart contact lenses represents a significant advancement toward safer wearable technologies. By leveraging MXene nanosheets’ properties, the lenses provide effective protection against high-frequency radiation while maintaining comfort and usability. Beyond eye health, this breakthrough paves the way for the integration of advanced nanomaterials in smart wearables, medical implants, and bioelectronics, addressing both safety and functionality.

Reference
“MXene-Integrated Contact Lens: A Breakthrough in Wearable Eye Protection and Healthcare”