Liquid Metal Functionalization Innovations in Wearables and Soft Robotics for Smart Healthcare Applications

Abstract

Smart healthcare solutions are crucial for early diagnosis, real‐time health monitoring, and personalized therapy. Essential to these advancements are flexible wearable devices and medical robotics, which incorporate a range of elements, including soft sensors, therapeutic modules, human‐machine interfaces, actuators, and systems for communication, computation, and power. Liquid metal‐based materials are rapidly emerging as one of the key elements for these innovations. This review will delve into the latest breakthroughs in liquid metal (LM) functionalization innovation and the applications in healthcare‐related wearables and soft robotics. Firstly, techniques to modify LM are explored, emphasizing strategies to enhance properties such as electromechanical, thermal, electromagnetic, biochemical, self‐healing, and magnetic capabilities. Next, the authors shed light on contemporary wearable sensors, therapeutic on‐skin devices, and other flexible device innovations. They finally conclude by highlighting the challenges and charting the path forward for LM‐driven healthcare advances.

Latest developments and trends in electronic skin devices

“…On the other hand, the self-healing function of e-skins needs to repair not only mechanical damage but also damage to the conductive pathways inside the device [166][167][168] . A fashionable approach is to use liquid metals (LM) with high conductivity and fluidity, such as eutectic gallium indium (EGaIn) alloys, Fe-particle doped EGaIn (Fe-EGaIn), to make e-skins [169][170][171][172][173][174] . The LM will form a shell with the surrounding resin matrix and air, encasing it inside.…”

Recent Advances in Wearable Healthcare Devices: From Material to Application

“…Flexible conductive hydrogels are widely used in wearable devices [81][82][83][84]. By incorporating conductive polymers, ionic conductive materials, and fillers, the conductivity of hydrogels can be significantly increased.…”

“…Also, due to its flow characteristics, it is possible to control the distribution of liquid metal in the device and self-healing of the metal pattern or metal network. LM can be modified to improve its application range, such as electromechanical functionalization, sintering [93][94][95], thermal functionalization [96,97], biochemical functionalization [83,98], electromagnetic [80] with permission; (d) images of PPT hydrogels exhibiting rapid self-healing abilities. Images reprinted from [85] with permission; (e) PBM can be reshaped after cutting in pieces; (f) Stretch curve of PBM hydrogel after self-healing at different times and healing efficiency of PBM hydrogels after tensile fracture healing.…”

“…Also, due to its flow characteristics, it is possible to control the distribution of liquid metal in the device and self-healing of the metal pattern or metal network. LM can be modified to improve its application range, such as electromechanical functionalization, sintering [93][94][95], thermal functionalization [96,97], biochemical functionalization [83,98], electromagnetic functionalization [99], magnetic functionalization [83,100], and self-healable functionalization [101]. To obtain self-healing properties, there are two main methods: exogenous self-healing methods, and the combination of healing agents based on microcapsules or microvessels ; and intrinsic self-healing methods, which rely on dynamic reversible covalent or non-covalent bonds to repair damaged areas (Figure 4a-c) [101].…”