Injectable, Self-Healing, β‑Chitin-Based Hydrogels with Excellent Cytocompatibility, Antibacterial Activity, and Potential As Drug/Cell Carriers

Dynamic chemistry has been recently applied to design injectable hydrogels capable of self-healing. Among current strategies for preparing hydrogels that are suitable for cell encapsulation and culture, the fabrication of injectable, self-healing hydrogels is immensely superior. Here, novel β-chitin-based, injectable, self-healing hydrogels were constructed through the self-assembly and entanglement of amphiphilic quaternized β-chitin (QC) and hydrophilic oxidized dextran (OD) chains as well as the dynamic Schiff base linkages without extra additives under physiological conditions. The gelation time, viscoelastic behavior, mechanical properties, biodegradability, stimulus sensitivity, shear-thinning ability and self-healing properties of the QC/OD hydrogels were thoroughly characterized. Moreover, the QC/OD hydrogels could be applied for the controlled pH-sensitive release of doxorubicin hydrochloride. Because of the excellent cytocompatibility, the QC/OD hydrogels were further used as a promising platform for the three-dimensional encapsulation and culture of NIH-3T3 cells and mouse bone marrow-derived mesenchymal stem cells. Specifically, these novel β-chitin-based hydrogels can be used as an antibacterial vehicle for the delivery of cells in the gel form and thus have potential for applications in regenerative medicine, drug/gene/cell delivery, and cell therapy