In Situ Forming, Dual-Crosslink Network, Self-Healing Hydrogel Enabled by a Bioorthogonal Nopoldiol–Benzoxaborolate Click Reaction with a Wide pH Range

The use of click chemistry as a hydrogel cross-linking reaction is often limited by slow reaction rates and harsh conditions, such as exposure to UV light and/or use of nonspecific or toxic reagents. On the other hand, the process of boronic ester formation between arylboronic acids and diols suffers from its intrinsic reversibility and low binding affinity at low pH, which impede its potential in many biomedical applications where a fast and stable click reaction is needed. Herein, we report a new concept of click hydrogel fabrication that combines a traditional sugar-based boronic ester and a novel nopoldiol-based benzoxaborolate as a dual-crosslink network (DCN) system. The cooperation of dynamic and rigid networks and the unique sensitivity of benzoxaborolate cross-links toward stimulus provide an intelligent hydrogel with a set of interesting features: (i) catalyst/light-free nopoldiol–benzoxaborolate bioorthogonal click cross-linking, (ii) rapid in situ formation within 26 s, (iii) wide self-healing...