Zwitterionic fusion in hydrogels and spontaneous and time-independent self-healing under physiological conditions.

The biomedical applications of current self-healing materials are largely impeded by their healing conditions, which usually require heating, UV exposure or harsh pH environments. At the same time, for very few existing spontaneously self-healing materials, healing can only be achieved immediately after rupture occurs. Here, we developed a spontaneously healing material, driven by a new mechanism, "zwitterionic fusion", which is repairable independent of time after damage under physiological conditions. We also tested the anti-fatigue property of this zwitterionic hydrogel. Furthermore, we utilized this zwitterionic fusion to link different cell-hydrogel constructs together.