Self-Powered Wearable Athletics Monitoring Nanodevice Based on ZnO Nanowire Piezoelectric-Biosensing Unit Arrays

A multifunctional piezoelectric-biosensor for motion detection and lactic acid analysis is fabricated from ZnO nanowire arrays, and it shows potential application in next generation of self-powered wearable athletics monitoring nano-system. The flexible skin-like device can be easily attached on the joints of athlete, which can real-time detect the running speed, stride frequency and joint angles during exercises through actively outputting piezoelectric signal (driven by the motion itself). The piezoelectric output voltage can be used as both the energy supply and sensing signal. After decorating lactate oxidase on ZnO nanowires, the device can also detect lactate concentration on athlete skin, and the analysis process is also powered by the motion energy. The sporting skill and physiological status have been discussed basing on the experimental data. The change of lactic acid concentration in sweat of the sports body is positively correlated with the running speed, which is in line with the law of physical movement and provides the basis for athletes' selection, performance monitoring and injury prevention. This multi-discipline research may point out a new developing orientation of sports science and may promote the development of flexible self-powered multifunctional nano-systems.