Tear-Based Battery Embedded with Prussian Blue Analogues and Silver Nanoparticles for Smart Contact Lenses

Area of Science:

• Materials Science
• Electrochemistry
• Biomedical Engineering

Background:

• Smart contact lenses offer significant potential for continuous, noninvasive healthcare monitoring.
• Conventional flexible battery fabrication methods face limitations due to stringent safety and nontoxicity requirements for ocular devices.

Purpose of the Study:

• To design and evaluate a safe, flexible, tear-based aqueous battery for integration into smart contact lenses.
• To address the safety and biocompatibility challenges of ocular electronic devices.

Main Methods:

• Fabrication of a flexible aqueous battery using Prussian blue analogues as the cathode and silver nanoparticle films as the anode.
• Electrochemical characterization, including cyclic performance, discharge capacity, and rate capability, in a tear-like solution at 34.5 °C.
• Assessment of mechanical stability and biocompatibility for ocular applications.

Main Results:

• The battery demonstrated satisfying cyclic electrochemical performance with a discharge capacity of 195.37 μAh within the voltage range of 0.2–1.0 V.
• The power and voltage output were sufficient to operate an integrated temperature sensor.
• The developed battery exhibited good mechanical stability and biocompatibility.

Conclusions:

• A novel, safe, and flexible tear-based aqueous battery has been successfully designed and demonstrated.
• This battery technology is suitable for powering sensors in smart contact lenses for continuous health monitoring.
• The findings pave the way for advanced, biocompatible electronic devices in ocular healthcare.