Three-Dimensionally Printed Interconnects for Smart Contact Lenses

Area of Science:

• Materials Science
• Biomedical Engineering
• Nanotechnology

Background:

• Smart contact lenses require miniaturized, interconnected devices for health monitoring.
• Existing interconnects face challenges with varying device thickness and material flexibility.

Purpose of the Study:

• To demonstrate a novel 3D interconnect fabrication method for smart contact lenses.
• To develop flexible, low-temperature processed interconnects compatible with contact lens materials.

Main Methods:

• Electrospraying of a silver-silver nanowire (Ag/AgNW) composite ink onto a polyimide substrate to create 3D patterns.
• Transferring the 3D patterns onto a contact lens platform.
• Characterization of sheet resistance and mechanical durability under deformation.

Main Results:

• Achieved sheet resistance of 0.396 Ω/□ for Ag/AgNW interconnects spanning a 300 μm height difference.
• Demonstrated enhanced durability, with only a 15.2% change in resistance under bending (3 mm radius), compared to 86.1% for pure silver.

Conclusions:

• The Ag/AgNW composite ink effectively creates robust, 3D-conforming interconnects for smart contact lenses.
• This method supports the development of advanced, flexible wearable health-monitoring devices.