A novel self-powered wearable motion sensor for monitoring the spiking gesture of volleyball athletes has been manufactured from piezoelectric PVDF film. The PVDF film can convert body mechanical energy into electricity through the piezoelectric effect, and the flexible device can be conformably attached on the hand or arm. The sensor can work independently without power supply and actively output piezoelectric signals as the sports information. The sensor can detect the tiny and fine motion of spiking movement in playing volleyball, reflecting the skill. Additionally, the sensor can also real-time monitor the pulse changes and language during a volleyball match. The self-powered sensors can link to a wireless transmitter for uploading the sports information and building big sports data. This work can provoke a new direction for real-time sports monitoring and promote the development of big sports data.

We fabricated wearable perspiration analyzing sites for actively monitoring physiological status during exercises without any batteries or other power supply. The device mainly consists of ZnO nanowire (NW) arrays and flexible polydimethylsiloxane substrate. Sweat on the skin can flow into the flow channels of the device through capillary action and flow along the channels to ZnO NWs. The sweat flowing on the NWs (with lactate oxidase modification) can output a DC electrical signal, and the outputting voltage is dependent on the lactate concentration in the sweat as the biosensing signal. ZnO NWs generate electric double layer (EDL) in sweat, which causes a potential difference between the upper and lower ends (hydrovoltaic effect). The product of the enzymatic reaction can adjust the EDL and influence the output. This device can be integrated with wireless transmitter and may have potential application in constructing sports big data. This work promotes the development of next generation of biosensors and expands the scope of self-powered physiological monitoring system.

The proper axial length of the eye is crucial for achieving emmetropia. In this study, we present a wireless battery-free eye modulation patch designed to correct high myopia and prevent relapse. The patch consists of piezoelectric transducers, an electrochemical micro-actuator, a drug microneedle array, μ-LEDs, a flexible circuit, and biocompatible encapsulation. The system can be wirelessly powered and controlled using external ultrasound. The electrochemical micro-actuator plays a key role in precisely shortening the axial length by driving the posterior sclera inward. This ensures accurate scene imaging on the retina for myopia eye. The drug microneedle array delivers riboflavin to the posterior sclera, and μ-LEDs’ blue light induces collagen cross-linking, reinforcing sclera strength. In vivo experiments demonstrate that the patch successfully reduces the rabbit eye’s axial length by ~1217 μm and increases sclera strength by 387%. The system operates effectively within the body without the need for batteries. Here, we show that the patch offers a promising avenue for clinically treating high myopia.

Neonatal jaundice refers to the abnormality of bilirubin metabolism for newborns, and wearable transcutaneous bilirubin meters for real-time measuring the bilirubin concentration is an insistent demand for the babies’ parents and doctors. In this paper, a self-powered wearable biosensor in a baby diaper for real-time monitoring neonatal jaundice has been realized by the hydrovoltaic-biosensing coupling effect of ZnO nanoarray. Without external power supply, the system can work independently, and the hydrovoltaic output can be treated as both the power source and biosensing signal. The working mechanism is that the hydrovoltaic output arises from the urine flowing on ZnO nanoarray and the enzymatic reaction on the surface can influence the output. The sensing information can be transmitted through a wireless transmitter, and thus the parents and doctors can treat the neonatal jaundice of babies in time. This work can potentially promote the development of next generation of biosensors and physiological monitoring system, and expand the scope of self-powered technique and smart healthcare area.