title: Thermoresponsive hyperbranched copolymer with multi acrylate functionality for in situ cross-linkable hyaluronic acid composite semi-IPN hydrogel.
abstract: Thermoresponsive polymers have been widely used for in situ formed hydrogels in drug delivery and tissue engineering as they are easy to handle and their shape can easily conform to tissue defects. However, non-covalent bonding and mechanical weakness of these hydrogels limit their applications. In this study, a physically and chemically in situ cross-linkable hydrogel system was developed from a novel thermoresponsive hyperbranched PEG based copolymer with multi acrylate functionality, which was synthesized via an 'one pot and one step' in situ deactivation enhanced atom transfer radical co-polymerization of poly(ethylene glycol) diacrylate (PEGDA, M(n) = 258 g mol(-1)), poly(ethylene glycol) methyl ether methacrylate (PEGMEMA, M(n )= 475 g mol(-1)) and (2-methoxyethoxy) ethyl methacrylate (MEO(2)MA). This hyperbranched copolymer was tailored to have the lower critical solution temperature to form physical gelation around 37°C. Meanwhile, with high level of acrylate functionalities, a chemically cross-linked gel was formed from this copolymer using thiol functional cross-linker of pentaerythritol tetrakis (3-mercaptopropionate) (QT) via thiol-ene Michael addition reaction. Furthermore, a semi-interpenetrated polymer networks (semi-IPN) structure was developed by combining this polymer with hyaluronic acid (HA), leading to an in situ cross-linkable hydrogel with significantly increased porosity, enhanced swelling behavior and improved cell adhesion and viability both in 2D and 3D cell culture models.
authors.affiliation: Network of Excellence for Functional Biomaterials, National University of Ireland, Galway, Ireland.
authors.forename: Yixiao
authors.initials: Y
authors.lastname: Dong
authors.forename: Waqar
authors.initials: W
authors.lastname: Hassan
authors.forename: Yu
authors.initials: Y
authors.lastname: Zheng
authors.forename: Aram Omer
authors.initials: AO
authors.lastname: Saeed
authors.forename: Hongliang
authors.initials: H
authors.lastname: Cao
authors.forename: Hongyun
authors.initials: H
authors.lastname: Tai
authors.forename: Abhay
authors.initials: A
authors.lastname: Pandit
authors.forename: Wenxin
authors.initials: W
authors.lastname: Wang
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D003432:Cross-Linking Reagents / Q000737:chemistry; D006358:Hot Temperature; D006820:Hyaluronic Acid / Q000737:chemistry*; D020100:Hydrogels; D011108:Polymers / Q000737:chemistry*; D011817:Rabbits
chemical_list: D003432:Cross-Linking Reagents; D020100:Hydrogels; D011108:Polymers; D006820:Hyaluronic Acid