Biological Tissue-Inspired Living Self-Healing Hydrogels Based on Cadherin-Mediated Specific Cell-Cell Adhesion.

Regarding synthetic self-healing materials, as healing reactions occur at the molecular level, bond formation occurs when healing chemicals are nanometer distances apart. However, motility of healing chemicals in materials is quite limited, permitting only passive diffusion, which reduces the chance of bond formation. By contrast, biological-tissues exhibit significant high-performance self-healing, and cadherin-mediated cell-cell adhesion is a key mechanism in the healing process. This is because cells are capable of a certain level of motility and actively migrate to damage sites, thereby achieving cell-cell adhesion with high efficacy. Here, we report biological-tissue-inspired, self-healing hydrogels in which azide-modified living cells are covalently cross-linked with alkyne-modified alginate polymers via bioorthogonal reactions. As a proof-of-concept, we demonstrate their unique self-healing capabilities originating from cadherin-mediated adhesion between cells incorporated into the gels as mobile healing mechanism. This study provides an example of self-healing material incorporating living components into a synthetic material to promote self-healing.