Hierarchically structured vertical gold nanowire array-based wearable pressure sensors for wireless health monitoring

We have recently demonstrated that vertically aligned gold nanowires (v-AuNWs) are outstanding material candidates for wearable biomedical sensors toward real-time and noninvasive health monitoring because of their excellent tunable electrical conductivity, biocompatibility, chemical inertness, and wide electrochemical window. Here, we show that v-AuNWs could also be used to design a high-performance wearable pressure sensor when combined with rational structural engineering such as pyramid microarray-based hierarchical structures. The as-fabricated pressure sensor featured a low operation voltage of 0.1 V, high sensitivity in a low-pressure regime, a fast response time of <10 ms, and high durability with stable signals for the 10 000 cycling test. In conjunction with printed electrode arrays, we could generate a multiaxial map for spatial pressure detection. Furthermore, our flexible pressure sensor could be seamlessly connected with a Bluetooth low-energy module to detect high-quality artery pulses in a wireless manner. Our solution-based gold coating strategy offers the benefit of conformal coating of nanowires onto three-dimensional microstructured elastomeric substrates under ambient conditions, indicating promising applications in next-generation wearable biodiagnostics.