(Invited) Supramolecular Hydrogels for Fabrications of Wearable Sensors and Medical Scaffolds

While hydrogels have enabled a variety of applications in wearable sensors and electronic skins, they are susceptible to fatigue fracture during their cyclic deformations owing to the inefficient fatigue resistance. Design of hydrogels with excellent mechanical properties and highly stable performance during the practical long-term applications of produced wearable sensors and medical scaffolds remains a tremendous challenge. The supramolecular hydrogels with the topological networks consisting of mechanical interlocked units lead to high toughness and robust fracture resistance. In our studies, a type of polymerizable crosslinker is assembled by the precise host-guest recognition, which is then photocured to construct the conductive hydrogel system. This polymerizable crosslinker having the mobile junctions simultaneously endows the resulting conductive hydrogels with three important features in the applications of strain sensors and scaffolds: (1) high stretchability along with superior fatigue resistance, (2) hydrogels applicable for sensors with high conductivity and sensitivity, and (3) suitability for 3D printing fabrication of sensors with altitude complexity. In addition, we have developed a biological metabolism-inspired hydrogel from the dynamic cross-linked natural polymer for reshaping the hostile rheumatoid arthritis microenvironment. The engineered hydrogel exhibits injectable performance and self-healing ability. When the hydrogel is engineered as a 3D stem cell-laden scaffold, the satisfactory reconstruction of large-scale bone defects in rheumatoid arthritis is achieved with effective antioxidant and anti-inflammatory performance simultaneously.