Iontronic pressure sensor with a wide linearity range for "plug-and-play" fingertip pulse recording and statistical cardiovascular monitoring.

Cardiovascular diseases are a serious threat to humans. Arterial pulse monitoring using wearable electronics could help to assess the cardiac conditions of the wearer, which further reduces the possibility of a sudden lethal heart attack. However, pulse sensors are usually tightly bonded to the wrist during pulse monitoring. This scenario brings great discomfort to the wearer, but also causes unreliable pulse recording due to the susceptibility of motions and pressure sensing nonlinearity with high preload. To this end, a 3D-printed iontronic pressure sensor with high sensitivity (11.65 pF kPa-1) and ultrawide linearity range (150 kPa) was developed, which could monitor a fingertip pulse wave in a "plug-and-play" manner. The wide linearity range enabled the sensor to accurately record the fingertip pulse with variable applied preload, which dramatically improved the reliability of practical pulse sensing. The sensor was applied for monitoring the pulse of patients with cardiovascular diseases, and the correlation between disease type and characteristic pulse waveforms was analyzed. The superior pulse monitoring performance, as well as unprecedented operational convenience, highlights the great potential of the as-prepared pulse sensor in wearable health monitoring.