Microengineered 3D cell-laden thermoresponsive hydrogels for mimicking cell morphology and orientation in cartilage tissue engineering
Authors: Jingxiu Bi
Chia-Ming Fan
Nasim Annabi
Ali Tamayol
Bo Jin
Hu Zhang
Amir Mellati
Cory Xian
Ali Khademhosseini
Sheng Dai
Journal: Biotechnology and Bioengineering (2017)
Discipline: BIOLOGY & BIOCHEMISTRY
Keywords: cartilage tissue engineering; microfabrication; thermoresponsive hydrogel; zonal organization.
Affiliations: School of Chemical Engineering, The University of Adelaide, Adelaide, SA, 5005, Australia., School of Pharmacy and Medical Sciences, Sansom Institute for Health Research, University of South Australia, Adelaide, SA, Australia., 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., Department of Bioindustrial Technologies, College of Animal Bioscience and Technology, Konkuk University, Hwayang-dong, Gwangjin-gu, Seoul 143-701, Republic of Korea.

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. 

Retracted: No

PubPeer comments:
 Figure 3. * Blue boxes: Panels a (Day 14) and b (Day 28) appear to show the same tissue section, albeit at a different zoom factor. ![file] , 
 Erratum, August 2022: https: onlinelibrary.wiley.com doi 10.1002 bit.27917  This erratum is being published to correct the mistake in Figure 3 caption, we wrote Figures 3a and 3b for different magnifications for H E staining images. The Figure 3 caption u201cFigure 3. Histological and immunohistochemical staining of the cell-seeded hydrogels. (a and b) Sections were stained with H E at (a) day 14 and (b) day 28; (c and d) sections were stained with Safranin O for GAGs after (c) 14 days and (d) 28 days of incubation; and (f and g) sections were immunohistochemically stained for collagen type II after (e) 14 days and (f) 28 days of incubation. (scale bar [a] 200u2009mm, 4; [bu2013g] 50u2009mm, 10.)u201d should read u201cFigure 3. Histological and immunohistochemical staining of the cell-seeded hydrogels. (a and b) Sections were stained with H E at (a) day 14 at a low magnification and (b) at a high magnification; (c and d) sections were stained with Safranin O for GAGs after (c) 14 days and (d) 28 days of incubation; and (f and g) sections were immunohistochemically stained for collagen type II after (e) 14 days and (f) 28 days of incubation (scale bar [a] 200u2009mm, 4; [bu2013g] 50u2009mm, 10.).u201d All other parts are unchanged. The authors regret these errors. ,