All-small-molecule dynamic covalent hydrogels with multistimuli responsiveness

Low molecular weight hydrogels have shown great promise in cell culture, tissue engineering, and controlled drug release. They are generally constructed from small molecules that form fibrous networks in aqueous solutions via supramolecular assembly. Here, we report a class of all-small-molecule dynamic covalent hydrogels via formaldehyde condensation with aminoglycosides, a family of naturally occurring antibiotics consisting of oligosaccharides and multiple amine groups. The abundant hydroxyl groups on aminoglycosides facilitate the formation of a secondary network via intermolecular hydrogen bonding at room temperature. The aminoglycoside hydrogels show excellent pH- and temperature-responsiveness and display controllable stiffness in the presence of different alkali cations and halogen anions. This study provides a facile strategy to construct low molecular weight hydrogels with multistimuli-responsiveness, and modulable and recyclable properties.