Highly Sensitive Flexible Iontronic Pressure Sensor for Fingertip Pulse Monitoring

Abstract

The pulse is a key biomedical signal containing various human physiological and pathological information highly related to cardiovascular diseases. Pulse signals are often collected from the radial artery based on Traditional Chinese Medicine, or by using flexible pressure sensors. However, the wrist wrapped with a flexible pressure sensor exhibits unstable signals under hand motion because of the concave surface of the wrist. By contrast, fingertips have a convex surface and therefore show great promises in stable and long‐term pulse monitoring. Despite the promising potential, the fingertip pulse signal is weak, calling for highly sensitive detecting devices. Here, a highly sensitive and flexible iontronic pressure sensor with a linear sensitivity of 13.5 kPa−1, a swift response, and remarkable stability over 5000 loading/unloading cycles is developed. This sensor enables stable and high‐resolution detection of pulse waveform under both static condition and finger motion. Fingertip pulse waveforms from subjects of different genders, age, and health conditions are collected and analyzed, suggesting that fingertip pulse information is highly similar to that of the radial artery. This work justifies that fingertip is an ideal platform for pulse signals monitoring, which would be a competitive alternative to existing complex health monitoring systems.

Silver Nanotube Networks with Ultrahigh Strain Limit as Reliable Flexible Transparent Electrode and Tactile Sensor

“…The diverse applications of flexible electronics and wearable devices, [1][2][3][4] such as highly fitting electronic skins, [5,6] wearable human body signal sensing systems, [7][8][9] and flexible tactile interfaces, [10,11] have created a novel demand for lighter, thinner, softer, and lower-resistance devices to achieve more precise and smarter functions. [12][13][14][15] Due to the characteristics of lightness, thinness, and softness, flexible transparent electrodes in devices face more complex bending and twisting deformation, and the corresponding strain limit is put forward with higher requirements. [16,17] In the case of ultrahigh bending and torsion comprehensive deformation, it is a challenging task for the transparent electrode to maintain a considerably long service life, high transparency, and low square resistance.…”

Smart Materials Enabled with Artificial Intelligence for Healthcare Wearables

“…In recent years, pressure and strain sensors have became increasingly important in biomedical applications, including health diagnosis and the detection of physical and biological signals, such as blood flow, [181] pulse, [182] body motion, [183] and others. They have also played a major role in developing bioelectronics, soft robotics, [184] electronic and artificial skins, [185] as well as in human-machine interaction.…”

Bioinspired Design of Hill‐Ridge Architecture‐Based Iontronic Sensor with High Sensibility and Piecewise Linearity

“…The performance comparison of flexible pressure sensors based on iontronic sensing mechanism is provided in Table S2 (Supporting Information). [30,[43][44][45][46][47][48][49] Furthermore, the property of high-pressure resolution is evidenced in Figure 3f. The ridge-shaped part of HRA-based dielectric layer broadens the pressure range, making the sensor desaturated under high pressure.…”