Plant Inspired Tough,Adhesive And Antibacterial Hydrogel

Nowadays,since the adhesive hydrogel can adhere to tissues or other biological materials,preventing the materials from falling off,and can be applied to surgical sutures,tissue repair,and so on,it has been widely studied in biomedicine.However,most adhesive hydrogels do not have long-term and repeatable adhesiveness.In addition,traditional adhesive hydrogels generally exhibit poor mechanical properties and cell affinity and do not have bactericidal ability.Here,a plant-inspired tough,adhesive and antibacterial hydrogel has been developed based on Ag@Lignin nanoparticles(NPs)triggered dynamic redox catechol chemistry.Ag@Lignin NPs construct the dynamic catechol redox system,which creates long-lasting reductive-oxidative environment inner hydrogel networks.This redox system,generating catechol groups continuously,endows the hydrogel with long-term and repeatable adhesiveness.Furthermore,Ag@Lignin NPs generate free radical and trigger self-gelation of the hydrogel under ambient environment.This hydrogel presents high toughness for the existence of covalent and non-covalent interaction in the hydrogel networks.The hydrogel also exhibits good cell affinity and high antibacterial activity due to the catechol groups and bactericidal ability of Ag@Lignin NPs.This study proposes a strategy to design tough and adhesive hydrogels based on dynamic plant catechol chemistry.The main contents are divided into the following two parts:First,the tough,adhesive and antibacterial hydrogel is gelled from an aqueous precursor solution containing Ag@Lignin NPs,pectin,acrylic acid(AA),initiator and crosslinker under an ambient environment by free radical polymerization.PAA is the main network of hydrogel.Pectin interpenetrated into the PAA network and had covalent and non-covalent interaction with the PAA network to make the hydrogel tougher and more flexible.The functional groups of Ag@Lignin NPs form noncovalent interaction with the PAA and pectin,and therefore the NPs work as nano-reinforcement to improve the mechanical properties of the hydrogel.The nano-reinforcement and interpenetrating network structure synergistically enhance the mechanical properties of the hydrogel.The results of mechanical experiments show that Ag@Lignin NPs and pectin synergistically enhance the mechanical properties of hydrogels.In addition,since Ag@Lignin NPs in the hydrogel contains a large amount of phenolic hydroxyl groups and benzene rings,the adhesion to the surface of the tissue and the hydrophilic and hydrophobic materials can be achieved.The Ag in the Ag@Lignin NPs gives the hydrogel a broad-spectrum antimicrobial activity.Secondly,this study carried out various biological evaluations of hydrogels by in vitro and in vivo.The results showed that the hydrogel effectively and significantly inhibited both G-and G+ bacteria.The NPs-P-PAA hydrogel exhibited cell affinity and biocompatibility in vitro.The biocompatibility of hydrogel was improved due to the presence of lignin and pectin.The results of in vivo antibacterial animal experiments demonstrated that the NPs-P-PAA hydrogel had good antibacterial ability in vivo and can be safely applied for healing wounds and repairing bone or cartilage.This is because the lignin,PAA and pectin slow Ag release,so that the concentration is non-toxic to cells.Most interestingly,the hydrogel can repair the skin as a skin dressing,which can effectively promote the ability of skin tissue repair and regeneration.In summary,the tough,adhesive and antibacterial hydrogel has good mechanical properties,excellent long-term and repeated adhesion,stable and safe antibacterial properties and multiple properties such as cytocompatibility.This study proposes a strategy to design tough and adhesive hydrogels based on dynamic plant catechol chemistry,which is crucial for biomedical applications.