Supramolecular hydrogels cross-linked by preassembled host–guest PEG cross-linkers resist excessive, ultrafast, and non-resting cyclic compression

Poly(ethylene glycol) (PEG)-based hydrogels are promising materials for biomedical applications because of their excellent hydrophilicity and biocompatibility. However, conventional chemically cross-linked PEG hydrogels are brittle under mechanical loading. The mechanical resilience and rapid recovery abilities of hydrogel implants are critical in load-bearing tissues, such as articular cartilage, which are routinely subjected to cyclic loadings of high magnitude and frequency. Here, we report the fabrication of novel supramolecular PEG hydrogels by polymerizing N,N-dimethylacrylamide with supramolecular cross-linkers self-assembled from adamantane-grafted PEG and mono-acrylated β-cyclodextrin. The resultant PEG–ADA supramolecular hydrogels exhibit substantial deformability, excellent capacity to dissipate massive amounts of loading energy, and have a rapid, full recovery during excessive, ultrafast, and non-resting cyclic compression. Furthermore, the energy dissipation capacity of the PEG–ADA (adamantane-grafted Poly(ethylene glycol)) hydrogels can be regulated by changing the concentration, molecular weight and cross-linking density of PEG. According to in vitro cell metabolism and viability tests, the PEG–ADA hydrogels are non-cytotoxic. When placed over a monolayer of myoblasts that were subjected to instantaneous compressive loading, the PEG–ADA hydrogel cushion significantly enhanced cell survival under this deleterious mechanical insult compared with the effects of the conventional PEG hydrogel. Therefore, PEG–ADA hydrogels are promising prosthetic biomaterials for the repair and regeneration of load-bearing tissues.