A smart ball sensor fabricated by laser kirigami of graphene for personalized long-term grip strength monitoring

Grip strength is an important indicator of health conditions and needs to be monitored for health management. However, different populations (e.g., babies and rehabilitation patients) have different hand sizes and different levels of grip strengths, requiring a personalized sensor to monitor grip strength. In this paper, we developed a smart ball sensor by laser kirigami of graphene for personalized grip strength monitoring. To realize the rational utilization of space, a transparent pill shell embedding all electronic accessories is installed in the center of the ball sensor with a spiral-sensing unit fabricated by laser kirigami of graphene on the surface. Furthermore, we assessed the influence of contact area between hand and ball on grip strength using finite-element analysis (FEA), which was then considered in our results readout. The grip strength can be continuously read by a mobile phone in a wireless manner. The smart ball sensor demonstrated a high performance in vitro against gold-standard method in diseased and healthy subjects. It would be a powerful tool for personalized long-term monitoring of grip strength, especially suitable for specific populations such as babies and sensitive enough for samll grip strength.