Highly-sensitive linear tactile array for continuously monitoring blood pulse waves

This work presents the development of a tactile sensing array for continuous blood pulse wave monitoring. The polymer-based sensing device consists of two polydimethylsiloxane layers, which were patterned with microdomes transferred from nylon membrane filters. The microdomes form interlocked structures, which enable the tunneling piezoresistive effect and provide ultra-high sensitivity. The sensing array was designed in an 8 × 1 linear configuration, and the length-width ratio of each sensing element is about 8. This design facilitates the acquisition of blood pulse wave signals on the skin above a radial artery. The measured relationship between resistance and pressure force indicates that the sensor exhibits very high sensitivity (−6.08 kPa−1). The array sensing results revealed that crosstalk between the sensing elements was nominal. In addition, the repeatability testing also showed that the performance of the sensor was quite stable after 10,000 loading-unloading cycles.