3D-printed smart metamaterial implants that double as sensors to monitor spinal healing. (Credit: University of Pittsburgh)

Patient-specific 3D printed smart metamaterial implants double as sensors to monitor spinal healing. The new class of multifunctional mechanical metamaterials act as their own sensors, recording and relaying important information about the pressure and stresses on its structure. The so-called meta-tribomaterials (self-aware metamaterials), generate their own power and can be used for a wide array of sensing and monitoring applications.

The material is designed such that under pressure, contact-electrification occurs between its conductive and dielectric microlayers, creating an electric charge that relays information about the condition of the material matrix. In addition, it naturally inherits the outstanding mechanical tunability of standard metamaterials.

The power generated using its built-in triboelectric nanogenerator mechanism eliminates the need for a separate power source, and a tiny chip records data about the pressure on the cage, which is an important indicator of healing. The data can then be read noninvasively using a portable ultrasound scanner.