Recent advances in the application of nanogenerators in orthopedics: From body surface to implantation

Nanogenerators are devices that convert mechanical energy into electrical energy, which are widely used in wearable and health fields. Nanogenerators use the mechanical energy generated by human motion to drive nanogenerators to achieve biomedical applications or health monitoring. In this process, nanogenerators typically harness the triboelectric or piezoelectric effect to generate electrical energy, allowing efficient energy conversion even with small mechanical inputs from human motion. In human organs, bone, as a rigid support, often preserves a large amount of kinetic energy and is the organ with the most abundant residual energy. By collecting this kinetic energy from bones, nanogenerators can provide a consistent, low-power energy source, suitable for sustaining the long-term operation of small electronic devices. The related electrical signals can also be used to monitor the motion posture information of bones, joints, tendons, and other positions. Here, the application of nanogenerators in orthopedics is reviewed, and its typical application scenarios include in vivo and in vitro. In vivo applications are mainly sensing and accelerating tissue regeneration, while in vitro are mainly wearable sensing. On the basis of summarizing these classification applications, the problems and prospects of nanogenerators in orthopedic applications are also proposed.