Lab to Fab Process Using Ablation Lasers: A Lightweight, Flexible, and Biocompatible Microheater for Wearable Therapy Applications

Wearable thermal therapy has attained significant attention owing to its potential in various wearable and biomedical applications specifically targeted for accelerated wound healing using smart bandages. Here, in the current work, a large area, precision, and scalable fabrication methodology is proposed using an ultraviolet (UV)-based ablation laser as compared to conventional fabrication methods such as photolithography or printing. This laser-based approach is unique and offers rapid prototyping, superior material versatility, design flexibility, and minimal thermal damage to the emerging biocompatible polymer-based flexible substrates. A thin, flexible, and biocompatible microheater and an array (4 × 4) of diverse designs, including circular, hexagonal, and planar, were designed and fabricated on a gold-coated PAC substrate using the proposed ablation laser-based approach. Multiple heater sizes varying from small to extra-large were fabricated and are tailored for the targeted temperatures ranging from 30 °C to 100 °C for biomedical applications, especially wearable wound healing applications. Electrical and electrothermal characteristics revealed that the sheet resistance, thermal response, and response time vary with the structure and size of the microheaters. Further, mechanical flexibility and biocompatibility studies on the PAC, patterned gold electrodes, and polyimide substrate demonstrated excellent mechanical robustness and biocompatibility, clearly demonstrating its efficacy and ability for wearable and implantable applications. Finally, the proposed research paves the pathway for the fabrication of next-generation wearable and implantable biointegrated flexible microheater devices toward advanced thermal therapy solutions.