Engineering Smart Composite Hydrogels for Wearable Disease Monitoring

Abstract

Growing health awareness triggers the public’s concern about health problems. People want a timely and comprehensive picture of their condition without frequent trips to the hospital for costly and cumbersome general check-ups. The wearable technique provides a continuous measurement method for health monitoring by tracking a person’s physiological data and analyzing it locally or remotely. During the health monitoring process, different kinds of sensors convert physiological signals into electrical or optical signals that can be recorded and transmitted, consequently playing a crucial role in wearable techniques. Wearable application scenarios usually require sensors to possess excellent flexibility and stretchability. Thus, designing flexible and stretchable sensors with reliable performance is the key to wearable technology. Smart composite hydrogels, which have tunable electrical properties, mechanical properties, biocompatibility, and multi-stimulus sensitivity, are one of the best sensitive materials for wearable health monitoring. This review summarizes the common synthetic and performance optimization strategies of smart composite hydrogels and focuses on the current application of smart composite hydrogels in the field of wearable health monitoring.

Deep-Learning Enabled Active Biomimetic Multifunctional Hydrogel Electronic Skin

“…Recently, hydrogels have received widespread interest because their mechanical structures and physical properties are similar to those of human tissue, and they have notable benefits of ultrahigh flexibility, exceptional stretchability, transparency in the visible spectrum, tunable conductivity, and intrinsic biocompatibility. − Hydrogels have been utilized in multiple kinds of sensors (temperature, humidity, strain, gases, etc.) and triboelectric nanogenerators for human–machine interfaces (HMIs). − The ions inside the ionic conductive hydrogels endow them with good conductivity. − The porous structure of the hydrogel provides effective channels for the conduction of ions.…”

Intrinsically Stretchable Conductive Self-Healable Organogels for Strain, Pressure, Temperature, and Humidity Sensing

“…Furthermore, conformable and stretchable temperature sensors can be employed to monitor the health care qualities of babies and patients under anesthesia as potential alternates of traditional hard mercury-based thermometers . Although researchers have reported conductive gels as different types of sensors, ,,– it is still a challenge to develop mechanically stable and self-healable conductive gels that can act as strain, pressure, temperature, and humidity sensors as a single sensing element with multiple sensing functions.…”

Flame‐retardant, flexible, and breathable smart humidity sensing fabrics based on hydrogels for respiratory monitoring and non‐contact sensing

“…When exposed to an open fire, it absorbs heat by evaporating water, dilutes oxygen by releasing CO 2 , and insulates oxygen by laminating on the fabric surface 49 . Compared to conventional halogen flame retardants and phosphorus flame retardants, hydrogels produce little toxic hydrogen halide gas and offer reduced smoke production, lower volatility, and higher efficiency 50,51 …”