Self-healing gels based on reshuffling disulfide bonds have attracted great attention due to their ability to restore structure and mechanical properties after damage. In this work, self-healing gels with different cellulose nanocrystals (CNC) contents were prepared by embedding the thiuram disulfide bonds into gels via polyaddition. By the reshuffling of thiuram disulfide bonds, the CNC-containing gels repair the crack and recover mechanical properties rapidly under visible light in air. The thiuram disulfide-functionalized gels with a CNC content of 2.2% are highly stretchable and can be stretched approximately 42.6 times of their original length. Our results provide useful approaches for the preparation of dynamic CNC-containing gels with implications in many related engineering applications.

Hydrogels have drawn intensive attention as fascinating materials for biomedicine. However, fabricating hydrogels with injectable and self-healing properties remains a challenge. Herein, we reported a biocompatible poly(N-vinylpyrrolidone)/carboxymethyl cellulose (PVP/CMC) hydrogel with excellent injectable and self-healing properties. The PVP/CMC hydrogel exhibits good biocompatible, injectable, and self-healing properties. The sol-gel transition of PVP/CMC hydrogels demonstrates an outstanding self-healing behavior, and the bisected hydrogels can self-heal within 30 s. The hydrogels have a good swelling ratio, and the swelling ratio increases with increasing amount of CMC in PVP and reaches a maximum of 2850% at a 1.0:1.5 PVP and CMC ratio. In addition, the hydrogel possesses excellent drug release capacity, and its drug release rate reaches 70%. Moreover, the release of 4-aminosalicylic acid (4-ASA) in the hydrogel can be controlled by adjusting the proportion of the hydrogel. The PVP/CMC hydrogel with excellent biocompatible, injectable, and self-healing properties has great potential for applications in drug release.

Conventional adhesives have poor underwater adhesion and harm to human health and the environment during their use, which largely limits their practical applications. Herein, we synthesized cellulose-based adhesives with underwater adhesion and biocompatibility by grafting N-(3,4-dihydroxyphenethyl)methacrylamide into the cellulose chain via atom transfer radical polymerization (ATRP). FTIR, ¹H NMR, and XPS analyses ensured the successful preparation of the cellulose-based adhesive polymers. The different properties of the prepared adhesives, including swelling ratio, adhesion strength, and biocompatibility are examined. Results found that the lap shear strength is enhanced by increasing the catechol content. When catechol content is 27.2 mol %, cellulose-based adhesive with the addition of Fe³⁺ possesses a strong lap shear strength of 2.13 MPa in a dry environment, 0.10 MPa underwater, and 0.16 MPa under seawater for iron substrate, respectively. In addition, the cell culture test demonstrated that the prepared adhesives have outstanding biocompatibility. The cellulose-based adhesives with underwater adhesion and biocompatibility have potential applications in biomedicine, electronic engineering, and construction fields.