In this study, a new series of 16 methyl salicylate derivatives bearing a piperazine moiety were synthesized and characterized. The in vivo anti-inflammatory activities of target compounds were investigated against xylol-induced ear edema and carrageenan-induced paw edema in mice. The results showed that all synthesized compounds exhibited potent anti-inflammatory activities. Especially, the anti-inflammatory activities of compounds M15 and M16 were higher than that of aspirin and even equal to that of indomethacin at the same dose. In addition, the in vitro cytotoxicity activities and anti-inflammatory activities of four target compounds were performed in RAW264.7 macrophages, and compound M16 was found to significantly inhibit the release of lipopolysaccharide (LPS)-induced interleukin (IL)-6 and tumor necrosis factor (TNF)-α in a dose-dependent manner. In addition, compound M16 was found to attenuate LPS induced cyclooxygenase (COX)-2 up-regulation. The current preliminary study may provide information for the development of new and safe anti-inflammatory agents.

Polyacrylamide/sodium alginate (PAM/SA) hydrogel was prepared from sodium alginate (SA) and acrylamide (AM) by covalently cross-linking. Temporary shape double network PAM/SA hydrogels were obtained by ionic cross-linking formed by complexation of SA and six metal cations (Fe³⁺, Cu²⁺, Ag⁺, Ca²⁺, Ni²⁺, and Co²⁺), among the PAM/SA—Fe³⁺ hydrogels has the best shape fixity ratio (83%). When the hydrogel is placed in different recovery liquids (sodium citrate, EDTA, sulfuric acid, and potassium carbonate), the shape recovery ratio (98.9%) is the best in sodium citrate solution, and the recovery time (182 s) of the hydrogel is the shortest. In general, Fe³⁺, Cu²⁺, and Ag⁺ are suitable for the construction of ionic-shape memory hydrogels. The PAM/SA hydrogels also exhibited excellent adjustable mechanical properties by changing metal cations and soaking time. The strategy could broaden the construction of ion-responsive shape-memory hydrogels.

Gelatin-UPy based on gelatin with ureidopyrimidinone (UPy) side chains was prepared with varying content of UPy units. On increasing the UPy content, the glass transition temperature, crystallinity and swelling decreased. Gelatin-UPy demonstrated self-healing properties as the UPy units could reversibly form dimers. At the same time, the gelatin-UPy and gelatin-UPy hydrogels demonstrated thermal responsive shape memory behaviors. The introduction of coordination crosslinking by introducing Fe³⁺ in gelatin-UPy hydrogels not only enhanced the crosslinking degree of gelatin-UPy and decreased the swelling degree, but also significantly improved the self-healing properties. As a drug carrier, gelatin-UPy hydrogels could achieve controlled release of 5-fluorouracil (5-FU) drug on increasing the content of UPy and concentration of Fe³⁺. The gelatin-UPy based materials are expected to find significant use as suppository and tissue engineering materials to treat tumors.