Layered, tunable graphene oxide-nylon composite heterostructures for wearable electrocardiogram sensors

Nanoscale engineered materials combined with wearable wireless technologies can deliver a new level of health monitoring. A reduced graphene oxide-nylon composite material is developed and tested, demonstrating its usefulness as a material for sensors in wearable, long-term electrocardiogram (ECG) monitoring via a comparison to one of the widely used ECG sensors. The structural analysis by scanning electron microscopy and atomic force microscopy shows a limited number of defects on a macroscopic scale. Fourier transform infrared and Raman spectroscopy confirm the presence of rGO_x, and the ratio of D- and G-features as a function of thickness correlates with the resistivity analysis. The negligible effect of the defects and the tunability of electrical and optical properties, together with live ECG data, demonstrate its signal transduction capability. Other potential electronic and optical sensor uses beyond ECG are possible, given the controllable nature of the heterostructures and the correlation of transport and optical properties.