Wireless Nanomembrane Electronics and Soft Packaging Technologies for Noninvasive, Real-time Monitoring of Muscle Activities

Volumetric muscle loss (VML) indicates the traumatic or surgical loss of skeletal muscle tissues, which leads to chronic muscle weakness and impaired muscle function. VML is a demanding issue since it requires surgical autologous muscle transplantation, which causes substantial morbidity to the donor site. Several researchers have studied VML on craniofacial muscles of large animals, such as zygomaticus muscles of sheep, emphasizing the pathophysiological differences between limb and craniofacial VML. However, a craniofacial VML mouse model using actual craniofacial muscles has not been reported due to the small size of the craniofacial muscle of a mouse. Another difficulty in developing the craniofacial VML mouse model is the lack of functional assay tools that can monitor the regeneration or recovery of injured muscles in the active mouse in a non-invasive manner. Current electromyogram (EMG) systems have limitations due to the form factor, rigidity, and bulky platforms, which require invasive needle-type sensors, wires, and multiple electronic modules. Here, we introduce thin-film, wireless nanomembrane electronics to measure noninvasive, real-time muscle EMG on the skin of mouse masseter muscles with or without biopsy punch-induced VML. The integration of soft materials, flexible structures, membrane electronics, and soft packaging technologies develop the all-in-one wearable sensor system that can be mounted on the skin. To measure the function of VML-injured masseter muscles of active mice, we use a soft, wireless, and wearable electronic system to provide real-time EMG monitoring. Overall, the presented study, integrating sensors, electronics, and packaging technologies, shows a wearable assay tool for the mechanism study and the therapeutic development of craniofacial VML.