A universal post-treatment strategy for biomimetic composite hydrogel with anisotropic topological structure and wide...

The development of biomimetic materials with anisotropic topological structure and wide range of adjustable mechanical properties is central to tissue engineering fields. In this work, on the basis of a stiff/stretchable dually crosslinked hydrogel, we paid more attention to the synergistic contribution of the confined drying and re-swelling (CDR) effect and Hofmeister effect to its micro structures, polymer aggregation states and mechanical strength. Specifically, by changing the pre-strains of the CDR procedure and the soaking time during the salting-out procedure, the arrangement structure orientation, chain-entanglement density, and supramolecular interaction strength within the polymer can be adjusted by changing the processing sequence of the two procedures, so that to obtain anisotropic biomimetic hydrogels with adjustable mechanical properties in a wide range. Thus, this engineered anisotropic polymer can mimic the natural tissues' mechanical properties in regeneration. Moreover and importantly, these anisotropic hydrogels exhibit prominent self-recovery properties. In summary, with the integration of molecular and structural engineering approaches, this study presents a universal strategy for developing anisotropic hydrogels, which could be widely used as biomimetic substitutes with anisotropic features in tissue regeneration.