title: Microengineered 3D cell-laden thermoresponsive hydrogels for mimicking cell morphology and orientation in cartilage tissue engineering.
abstract: Mimicking the zonal organization of native articular cartilage, which is essential for proper tissue functions, has remained a challenge. In this study, a thermoresponsive copolymer of chitosan-g-poly(N-isopropylacrylamide) (CS-g-PNIPAAm) was synthesized as a carrier of mesenchymal stem cells (MSCs) to provide a support for their proliferation and differentiation. Microengineered three-dimensional (3D) cell-laden CS-g-PNIPAAm hydrogels with different microstripe widths were fabricated to control cellular alignment and elongation in order to mimic the superficial zone of natural cartilage. Biochemical assays showed six- and sevenfold increment in secretion of glycosaminoglycans (GAGs) and total collagen from MSCs encapsulated within the synthesized hydrogel after 28 days incubation in chondrogenic medium. Chondrogenic differentiation was also verified qualitatively by histological and immunohistochemical assessments. It was found that 75 ± 6% of cells encapsulated within 50 μm wide microstripes were aligned with an aspect ratio of 2.07 ± 0.16 at day 5, which was more organized than those observed in unpatterned constructs (12 ± 7% alignment and a shape index of 1.20 ± 0.07). The microengineered constructs mimicked the cell shape and organization in the superficial zone of cartilage whiles the unpatterned one resembled the middle zone. Our results suggest that microfabrication of 3D cell-laden thermosensitive hydrogels is a promising platform for creating biomimetic structures leading to more successful multi-zonal cartilage tissue engineering. Biotechnol. Bioeng. 2017;114: 217-231. © 2016 Wiley Periodicals, Inc.
authors.affiliation: School of Chemical Engineering, The University of Adelaide, Adelaide, SA, 5005, Australia.
authors.forename: Amir
authors.initials: A
authors.lastname: Mellati
authors.affiliation: School of Pharmacy and Medical Sciences, Sansom Institute for Health Research, University of South Australia, Adelaide, SA, Australia.
authors.forename: Chia-Ming
authors.initials: CM
authors.lastname: Fan
authors.affiliation: Biomaterials Innovation Research Center, Division of Biomedical Engineering, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02139.|Harvard-Massachusetts Institute of Technology Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139.|Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, Massachusetts, 02115.
authors.forename: Ali
authors.initials: A
authors.lastname: Tamayol
authors.affiliation: Biomaterials Innovation Research Center, Division of Biomedical Engineering, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02139.|Harvard-Massachusetts Institute of Technology Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139.|Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, Massachusetts, 02115.|Department of Chemical Engineering, Northeastern University, Boston, Massachusetts.
authors.forename: Nasim
authors.initials: N
authors.lastname: Annabi
authors.affiliation: School of Chemical Engineering, The University of Adelaide, Adelaide, SA, 5005, Australia.
authors.forename: Sheng
authors.initials: S
authors.lastname: Dai
authors.affiliation: School of Chemical Engineering, The University of Adelaide, Adelaide, SA, 5005, Australia.
authors.forename: Jingxiu
authors.initials: J
authors.lastname: Bi
authors.affiliation: School of Chemical Engineering, The University of Adelaide, Adelaide, SA, 5005, Australia.
authors.forename: Bo
authors.initials: B
authors.lastname: Jin
authors.affiliation: School of Pharmacy and Medical Sciences, Sansom Institute for Health Research, University of South Australia, Adelaide, SA, Australia.
authors.forename: Cory
authors.initials: C
authors.lastname: Xian
authors.affiliation: Biomaterials Innovation Research Center, Division of Biomedical Engineering, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02139.|Harvard-Massachusetts Institute of Technology Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139.|Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, Massachusetts, 02115.|Department of Bioindustrial Technologies, College of Animal Bioscience and Technology, Konkuk University, Hwayang-dong, Gwangjin-gu, Seoul 143-701, Republic of Korea.
authors.forename: Ali
authors.initials: A
authors.lastname: Khademhosseini
authors.affiliation: School of Chemical Engineering, The University of Adelaide, Adelaide, SA, 5005, Australia.
authors.forename: Hu
authors.initials: H
authors.lastname: Zhang
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry; D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry*; D002356:Cartilage / Q000166:cytology*; D002454:Cell Differentiation; D002478:Cells, Cultured; D048271:Chitosan / Q000031:analogs & derivatives / Q000737:chemistry; D020100:Hydrogels / Q000737:chemistry*; D059630:Mesenchymal Stem Cells / Q000166:cytology; D051379:Mice; D055616:Microtechnology; D013499:Surface Properties; D013696:Temperature; D023822:Tissue Engineering / Q000379:methods*
chemical_list: D000180:Acrylic Resins; D001672:Biocompatible Materials; D020100:Hydrogels; D048271:Chitosan
keywords: cartilage tissue engineering; microfabrication; thermoresponsive hydrogel; zonal organization