Laser Direct-Write Sensors On CFR-PEEK For Smart Orthopedic Implants

Carbon-fiber-reinforced polyetheretherketone (CFR-PEEK) has been successfully applied in orthopedic implants, and loading progression of implants is crucial for the post-surgery study of fracture union and failure of prostheses. However, how to monitor the strain of CFR-PEEK-based implants remains a great challenge. In this work, a laser direct writing method has been used to produce highly conductive laser-annealing CFR-PEEK (LACP) and in-situ LACP-based strain sensors on CFR-PEEK-based implant parts for the first time. We conducted the fundamental study of the laser annealing mechanism of CFR-PEEK and PEEK, and optimized laser processing parameters to achieve low sheet resistance down to ~ 1.6 ohm/sq. A strain sensor has been fabricated with excellent linearity (R ² = 0.997) over the working range and realized wireless transmission using a Bluetooth module. This technique paves the way for timely loading progressing monitoring and personalized diagnostic applications.