An integrally formed Janus supramolecular bio-gel with intelligent adhesion for multifunctional healthcare

Despite the rapid development of Janus adhesive hydrogels, most of them still entail complex fabrication processes and have the inherent flaws, such as fragility and instability, thereby restricting their biomedical applications. In this study, a novel Janus bio-gel with strong mechanical and intelligent adhesion functions is facilely fabricated through a gravity-driven settlement strategy, employing poly-cyclodextrin microspheres (PCDMs). This strategy takes advantage of the sedimentation behavior of PCDMs with various diameters to establish structural disparities on both sides of the Janus bio-gel, thereby resolving multiple predicaments including the tedious synthesis steps and poor bonding of multilayer hydrogels. Owing to the multiple dynamic interactions between polymers and PCDMs, the Janus supramolecular bio-gel demonstrates outstanding mechanical toughness (1.97 MJ/m³) and elongation rate (≈800 %). More attractively, the resulting Janus bio-gel exhibits remarkable adhesiveness (316.4 J/m² for interfacial toughness) and adhesive differences that are exceed 50 times between the two surfaces. Furthermore, the Janus supramolecular bio-gel also has excellent antibacterial properties, biocompatibility, environmental stability, and multiple monitoring functions, accelerating wound stably healing and monitoring physiologic parameters on the skin. This strategy provides a straightforward and promising approach to directly achieve multifunctional integration for smart health management.