Applications of nanogenerator-based wearable devices in orthopedics

As an important part of internet of things (IOTs), wearable devices can provide real time monitoring for each individual and have shown the potential in personalized medical treatment. Orthopedics is an important branch of surgery and it focus on the injuries and disorders of musculoskeletal system. With the acceleration of population aging, the incidence of both chronic and acute orthopedics diseases is increasing, leading to significant public health and economic burden. Wearable devices have broad application prospects in diagnosis, treatment and post-rehabilitation monitoring of orthopedic diseases. However, batteries have limitations of inconvenient charging, service life, which greatly hinder the long-term applications of wearable devices. As a positive energy conversion device, nanogenerators (NGs) can convert the biomechanical energy generated by daily activities into electricity. The device can be applied not only for energy supply, but also as a self-powered sensor. This review concludes the working principles and material design strategies of several kinds of NGs, summarizes the applications of nanogenerator-based (NG-based) wearable devices in orthopedics, and prospects the opportunities and challenges that such devices will face in the future. This review may inspire further development of NG-based wearable devices and their applications in orthopedics.