title: Mussel-Inspired Adhesive and Tough Hydrogel Based on Nanoclay Confined Dopamine Polymerization.
abstract: Adhesive hydrogels are attractive biomaterials for various applications, such as electronic skin, wound dressing, and wearable devices. However, fabricating a hydrogel with both adequate adhesiveness and excellent mechanical properties remains a challenge. Inspired by the adhesion mechanism of mussels, we used a two-step process to develop an adhesive and tough polydopamine-clay-polyacrylamide (PDA-clay-PAM) hydrogel. Dopamine was intercalated into clay nanosheets and limitedly oxidized between the layers, resulting in PDA-intercalated clay nanosheets containing free catechol groups. Acrylamide monomers were then added and in situ polymerized to form the hydrogel. Unlike previous single-use adhesive hydrogels, our hydrogel showed repeatable and durable adhesiveness. It adhered directly on human skin without causing an inflammatory response and was easily removed without causing damage. The adhesiveness of this hydrogel was attributed to the presence of enough free catechol groups in the hydrogel, which were created by controlling the oxidation process of the PDA in the confined nanolayers of clay. This mimicked the adhesion mechanism of the mussels, which maintain a high concentration of catechol groups in the confined nanospace of their byssal plaque. The hydrogel also displayed superior toughness, which resulted from nanoreinforcement by clay and PDA-induced cooperative interactions with the hydrogel networks. Moreover, the hydrogel favored cell attachment and proliferation, owning to the high cell affinity of PDA. Rat full-thickness skin defect experiments demonstrated that the hydrogel was an excellent dressing. This free-standing, adhesive, tough, and biocompatible hydrogel may be more convenient for surgical applications than adhesives that involve in situ gelation and extra agents.
authors.affiliation: Key Lab of Advanced Technologies of Materials, Ministry of Education, School of Materials Science and Engineering, Southwest Jiaotong University , Chengdu 610031, Sichuan, China.
authors.forename: Lu
authors.initials: L
authors.lastname: Han
authors.affiliation: Key Lab of Advanced Technologies of Materials, Ministry of Education, School of Materials Science and Engineering, Southwest Jiaotong University , Chengdu 610031, Sichuan, China.|National Engineering Research Center for Biomaterials, Genome Research Center for Biomaterials, Sichuan University , Chengdu 610064, Sichuan, China.
authors.forename: Xiong
authors.identifier: 0000-0001-6367-430X
authors.initials: X
authors.lastname: Lu
authors.affiliation: Key Lab of Advanced Technologies of Materials, Ministry of Education, School of Materials Science and Engineering, Southwest Jiaotong University , Chengdu 610031, Sichuan, China.
authors.forename: Kezhi
authors.initials: K
authors.lastname: Liu
authors.affiliation: National Engineering Research Center for Biomaterials, Genome Research Center for Biomaterials, Sichuan University , Chengdu 610064, Sichuan, China.
authors.forename: Kefeng
authors.initials: K
authors.lastname: Wang
authors.affiliation: Department of Polymer Science and Engineering, School of Materials Science and Engineering, South China University of Technology of China , Guangzhou 510641, China.
authors.forename: Liming
authors.initials: L
authors.lastname: Fang
authors.affiliation: Department of Chemical and Biomolecular Engineering, Materials Characterisation and Preparation Facility, Department of Civil and Environmental Engineering The Hong Kong University of Science and Technology , Hong Kong, China.
authors.forename: Lu-Tao
authors.initials: LT
authors.lastname: Weng
authors.affiliation: Engineering Research Center of Biomass Materials, Ministry of Education, School of Materials Science and Engineering, Southwest University of Science and Technology , Mianyang 621010, China.
authors.forename: Hongping
authors.initials: H
authors.lastname: Zhang
authors.affiliation: Centre for NanoScale Science and Technology and School of Computer Science, Engineering, and Mathematics, Flinders University , Adelaide 5042, South Australia, Australia.
authors.forename: Youhong
authors.initials: Y
authors.lastname: Tang
authors.affiliation: Department of Materials Science and Engineering, South University of Science and Technology , Shenzhen, Guangdong 518055, China.
authors.forename: Fuzeng
authors.initials: F
authors.lastname: Ren
authors.affiliation: Department of Materials Science and Engineering, South University of Science and Technology , Shenzhen, Guangdong 518055, China.
authors.forename: Cancan
authors.initials: C
authors.lastname: Zhao
authors.affiliation: Department of Chemical and Biomolecular Engineering, Materials Characterisation and Preparation Facility, Department of Civil and Environmental Engineering The Hong Kong University of Science and Technology , Hong Kong, China.
authors.forename: Guoxing
authors.initials: G
authors.lastname: Sun
authors.affiliation: Department of Chemical and Biomolecular Engineering, Materials Characterisation and Preparation Facility, Department of Civil and Environmental Engineering The Hong Kong University of Science and Technology , Hong Kong, China.
authors.forename: Rui
authors.initials: R
authors.lastname: Liang
authors.affiliation: Department of Chemical and Biomolecular Engineering, Materials Characterisation and Preparation Facility, Department of Civil and Environmental Engineering The Hong Kong University of Science and Technology , Hong Kong, China.
authors.forename: Zongjin
authors.initials: Z
authors.lastname: Li
keywords: adhesive hydrogel; mussel-inspired; nanoclay; polydopamine; tough hydrogel; wound dressing