Synthesis and Properties of Dynamic Hydrogels Based on Host-guest Chemistry of Cucurbit[8]uril and Its Two Different Homodimer Guests

Dynamic crosslinking based on host-guest interaction has shown a number of advantages in constructing injectable hydrogel to be used for biomacromolecules and cell delivery materials. However, it is difficult to dynamically adjust the performance of the hydrogel with only one kind of crosslinking point presented in the structure of the hydrogel. In this study, a two-component supramolecular dynamic cross-linking hydrogel system was designed, employing the host-guest interaction between cucurbit[8]uril (CB[8]) and its homodimer guests to form ternary complex at a ratio of 1/2. The azobenzene guest residues and the phenyl pyridinium guest motifs were introduced into the side chain of hydrogel backbone polymer, in which the azobenzene guest would weakly bind with CB[8] showing faster dynamics, and the phenyl pyridinium salt guest would tightly bind with CB[8] showing slower dynamics. A series of hydrogel materials with the same network structure but dynamically adjustable properties were prepared by adjusting the proportions of these two dynamic cross-linking points. The obtained hydrogel materials could continuously change their properties such as rheology mechanical properties, self-healing, shear thinning, stress relaxation behavior, and macromolecular drug release, all of which are essential in biomedical fields and thus showed great potential in relevant applications. [GRAPHICS] .