Thermally reduced graphene oxide-nylon membrane based epidermal sensor using vacuum filtration for wearable electrophysiological signals and human motion monitoring

We fabricated high-performance paper-based epidermal sensors on biocompatible nylon-membrane without utilizing any harmful chemicals & complicated processes. The proposed epidermal sensor was fabricated using thermally reduced graphene oxide and a nylon-membrane (TRGO/NM). The epidermal sensor (TRGO/NM) has been developed to reduce the usage of Ag/AgCl (sticky sensor). The sensor demonstrates high sensitivity (sheet resistance = 40 Omega/sq.), because skin-contact impedance was similar to 20K Omega at low frequency. We found that the TRGO/NM sensor developed micro-gaps on the surface of NM, which generated resistance changes under tensile and compressive strain. The TRGO/NM sensor shows fast response time (similar to 0.5 s), relaxation time (similar to 0.5 s), and a highly stable with an excellent bending-stretching response. We applied the epidermal sensor for obtaining electrocardiography (ECG), electroencephalography (EEG), and electromyography (EMG) as well as monitoring human motions also. The biocompatibility of the TRGO/NM sensor was confirmed by performing the cytotoxicity test. (C) 2019 Elsevier Ltd. All rights reserved.