Skin- and hair- inspired nanofibrious hydrogel composite as multimodal sensor for polysomnographic monitoring in sleep apnea syndrome.

Flexible sensors, particularly biomimetic hair-like sensors, have recently garnered considerable interest for the real-time monitoring of sleep apnea syndrome (SAS) due to their exceptional sensitivity in detecting subtle respiratory airflow. However, most existing designs are limited to structural emulation of hair with single-signal responses, while neglecting the critical role of skin-hair functional integration in biological mechanosensation. Herein, we address this limitation by developing skin-hair mimetic sensor based on alkaline-treated polyacrylonitrile/ionic liquid/electrostatic flocked‑carbon fibers (aPAN/IL/CFs) nanofibrous hydrogel. This hydrogel combines a conductive aPAN/IL hydrogel (skin mimic) with vertically aligned carbon fibers (hair analogs) fabricated through electrostatic flocking, thereby enabling multimodal airflow and mechanical strain detection for comprehensive multiparametric SAS monitoring. The aPAN/IL/CFs nanofibrous hydrogel exhibits exceptional sensitivity for airflow and strain sensor, including a rapid airflow response time of 0.10 s, a minimum detectable airflow velocity of 0.033 m s, and a fast tensile response time of 0.6 s with a maximum gauge factor (GF) of 76.1. Furthermore, the lightweight and self-adhesive aPAN/IL/CFs nanofibrous hydrogel facilitated seamless integration with medical devices for monitoring physiological signals for SAS patients, including oral-nasal breathing, abdominal respiration, and pulse detection during sleep. Beyond respiratory monitoring, this sensor also supports gesture recognition and communication for critically ill patients with impaired verbal abilities.