title: In situ formation of adhesive hydrogels based on PL with laterally grafted catechol groups and their bonding efficacy to wet organic substrates.
abstract: Adhesives with catechol moieties have been widely investigated in recent years. However, actually how much catechol groups for these mussel bio-inspired adhesives, especially in their natural form under physiological condition, is appropriate to bond with organic substrates has not been studied intensively. This study blends ε-polylysine (PL), featuring laterally grafted catechols under physiological conditions (pH 7.4), with oxidized dextran to form a hydrogel in situ via the Schiff base without introducing small cytotoxic molecules as crosslinking agents. It finds that the amount of catechol groups imposes an obvious influence on gelation time, swelling behavior, and hydrogel morphology. Both the storage modulus and adhesion strength are found to increase first and decrease afterwards with an increase of pendent catechol content. Furthermore, catechol hydrogen interactions and the decrease in the crosslink density derived from the decrease of amino groups on PL are simultaneously found to affect the storage modulus. Meanwhile, multiple hydrogen-bonding interactions of catechol with amino, hydroxyl, and carboxyl groups, which are in abundance on the surface of tissue, are mainly found to provide an adhesive force. The study finds that with more catechol, there is a greater chance that the cohesive force will weaken, making the entire adhesion strength of the hydrogel decrease. Using a cytotoxicity test, the nontoxicity of the hydrogel towards the growth of L929 cells is proven, indicating that hydrogels have potential applications in soft tissue repair under natural physiological conditions.
authors.affiliation: School of Materials Science and Engineering, and Tianjin Key Laboratory of Composite and Functional Materials, Tianjin University, Tianjin, 300072, China.
authors.forename: Mingming
authors.initials: M
authors.lastname: Ye
authors.affiliation: School of Materials Science and Engineering, and Tianjin Key Laboratory of Composite and Functional Materials, Tianjin University, Tianjin, 300072, China.
authors.forename: Rui
authors.initials: R
authors.lastname: Jiang
authors.affiliation: School of Materials Science and Engineering, and Tianjin Key Laboratory of Composite and Functional Materials, Tianjin University, Tianjin, 300072, China. zhaojin@tju.edu.cn.|Department of Polymer Materials, School of Materials Science and Engineering, Tianjin University, Tianjin, 300072, People's Republic of China. zhaojin@tju.edu.cn.
authors.forename: Jin
authors.initials: J
authors.lastname: Zhao
authors.affiliation: First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, Tianjin, 300000, China.
authors.forename: Juntao
authors.initials: J
authors.lastname: Zhang
authors.affiliation: School of Materials Science and Engineering, and Tianjin Key Laboratory of Composite and Functional Materials, Tianjin University, Tianjin, 300072, China.
authors.forename: Xubo
authors.initials: X
authors.lastname: Yuan
authors.affiliation: School of Materials Science and Engineering, and Tianjin Key Laboratory of Composite and Functional Materials, Tianjin University, Tianjin, 300072, China.
authors.forename: Xiaoyan
authors.initials: X
authors.lastname: Yuan
mesh_terms: D020100:Hydrogels; D008855:Microscopy, Electron, Scanning; D009930:Organic Chemicals / Q000737:chemistry; D011107:Polylysine / Q000737:chemistry*
chemical_list: D020100:Hydrogels; D009930:Organic Chemicals; D011107:Polylysine