Biocompatible Energy Harvester for Smart Knee Implants

Abstract Although total knee replacements (TKR) are generally considered highly successful, patient satisfaction may not always be sustained over time. Monitoring the performance of the replaced knee can lead to improved surgical outcomes. Triboelectric Nano Generator (TENG) can generate electrical energy to power a load sensor, enabling continuous monitoring of the total knee replacement and more specifically monitoring imbalance over time. The objective of this study is to create a TENG capable of handling body forces and generating enough electrical energy to power the sensors. This is achieved through the energy harvester, which generates electric power by utilizing the contact separation resulting from cyclic compressive loads. To enhance the electrical properties of the energy harvester, a keystroke shape was used as a TENG structure. Moreover, the favorable characteristics of biocompatibility of the materials used in this study carry significant importance, particularly in applications where compatibility with biological systems is essential. This makes them particularly well-suited for integration into total knee implants. The experiment was conducted in this study and showed that the keystroke TENG structure could generate around 20 V peak voltage 2 kN axial force was applied to the TENG at 1 Hz. Expanding this to an array design enables measuring pressure distribution across TKR.