Soft and Stretchable Wireless Skin Patch for Electrophysiological Recording

Developing soft and stretchable electronics that perform reliably during daily activity without limiting the users’ physical movements during daily activities is a challenge. In most cases to improve stretchability of inherently rigid electronic components of a circuit, the use of off-the-shelf components in conjunction with stretchable interconnects to mitigate the strain is one method to address this issue. Several strategies have been reported to make such a hybrid platform including utilizing serpentine metal films on stretchable substrates, coating metal, or conducting films on pre-stretched polymers, using liquid metal filled microfluidic channels, etc. While such methods have indeed proved effective when low range of strain is applied, they fail at high level of strain. Further, the fabrication process for most of these methods often require microfabrication and access to clean-room facilities which is costly and time consuming.<br/>Here we report a wireless skin patch for electrophysiological recordings such as electrocardiography (ECG) and electromyography (EMG). This patch consists of self-adhesive stretchable sensor and circuit patches. The circuit consist of highly soft and stretchable interconnect with more than 600% stretchability and includes conditioning, wireless communication, and power circuits. Over 60,000 cycling test of the interconnects under 30% of strain showed no change in electrical conductivities of interconnects. Further, the fabrication process is low coast, scalable and done using bench top equipment.<br/> <br/>In conclusion our approach is a low cost, time effective method of wireless circuit patches for electrophysiological recording. The low modulus and stretchability of the circuit patch allows the integration of ultrasoft sensors that can conform to the microscopic feature of skin and enables long term, mobile, low motion artifact, high quality health monitoring.