title: Thermoresponsive Semi-IPN Hydrogel Microfibers from Continuous Fluidic Processing with High Elasticity and Fast Actuation.
abstract: Hydrogels with rapid and strong response to external stimuli and possessing high elasticity and strength have been considered as platform materials for numerous applications, e.g., in biomaterials engineering. Thermoresponsive hydrogels based on semi-interpenetrating polymer networks (semi-IPN) featuring N-isopropylacrylamide with copolymers of poly(N-isopropylacrylamide-co-hydroxyethyl methacrylate) p(NIPAM-HEMA) chains are prepared and described. The copolymer was characterized by FTIR, NMR, and GPC. The semi-IPN structured hydrogel and its responsive properties were evaluated by dynamic mechanical measurements, SEM, DSC, equilibrium swelling ratio, and dynamic deswelling tests. The results illustrate that the semi-IPN structured hydrogels possess rapid response and high elasticity compared to conventional pNIPAM hydrogels. By using a microfluidic device with double coaxial laminar flow, we succeeded in fabricating temperature responsive ("smart") hydrogel microfibers with core-shell structures that exhibit typical diameters on the order of 100 μm. The diameter of the fibers can be tuned by changing the flow conditions. Such hydrogel fibers can be used to fabricate "smart" devices, and the core layer can be potentially loaded with cargos to incorporate biological function in the constructs. The platforms obtained by this approach hold promise as artificial "muscles", and also "smart" hydrogel carriers providing a unique biophysical and bioactive environment for regenerative medicine and tissue engineering.
authors.affiliation: State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Material Science and Engineering, Donghua University , 201620 Shanghai, P. R. China.|Materials Science and Technology of Polymers, MESA+ Institute of Nanotechnology, University of Twente , P.O. Box 217, 7500 AE Enschede, The Netherlands.
authors.forename: Yan
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Materials Science and Technology of Polymers, MESA+ Institute of Nanotechnology, University of Twente , P.O. Box 217, 7500 AE Enschede, The Netherlands.
authors.forename: Kaihuan
authors.identifier: http://orcid.org/0000-0002-7353-4180
authors.initials: K
authors.lastname: Zhang
authors.affiliation: State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Material Science and Engineering, Donghua University , 201620 Shanghai, P. R. China.
authors.forename: Jinghong
authors.initials: J
authors.lastname: Ma
authors.affiliation: Materials Science and Technology of Polymers, MESA+ Institute of Nanotechnology, University of Twente , P.O. Box 217, 7500 AE Enschede, The Netherlands.
authors.forename: G Julius
authors.identifier: http://orcid.org/0000-0003-4718-0507
authors.initials: GJ
authors.lastname: Vancso
keywords: core−shell hydrogel microfibers; microfluidics; p(NIPAM-HEMA); thermoresponsive polymers