Boundary mode lubrication of articular cartilage with a biomimetic diblock copolymer

Sun, Z., Feeney, E., Guan, Y., Cook, S. G., Gourdon, D., Bonassar, L. J. and Putnam, D. (2019) Boundary mode lubrication of articular cartilage with a biomimetic diblock copolymer. Proceedings of the National Academy of Sciences of the United States of America, 116(25), pp. 12437-12441. (doi: 10.1073/pnas.1900716116) (PMID:31164421) (PMCID:PMC6589671)

Abstract

We report the design of a diblock copolymer with architecture and function inspired by the lubricating glycoprotein lubricin. This diblock copolymer, synthesized by sequential reversible addition–fragmentation chain-transfer polymerization, consists of a cationic cartilage-binding domain and a brush-lubricating domain. It reduces the coefficient of friction of articular cartilage under boundary mode conditions (0.088 ± 0.039) to a level equivalent to that provided by lubricin (0.093 ± 0.011). Additionally, both the EC50 (0.404 mg/mL) and cartilage-binding time constant (7.19 min) of the polymer are comparable to purified human and recombinant lubricin. Like lubricin, the tribological properties of this polymer are dependent on molecular architecture. When the same monomer composition was evaluated either as an AB diblock copolymer or as a random copolymer, the diblock effectively lubricated cartilage under boundary mode conditions whereas the random copolymer did not. Additionally, the individual polymer blocks did not lubricate independently, and lubrication could be competitively inhibited with an excess of binding domain. This diblock copolymer is an example of a synthetic polymer with lubrication properties equal to lubricin under boundary mode conditions, suggesting its potential utility as a therapy for joint pathologies like osteoarthritis.

• Item Type: Articles
• Additional Information: This research was supported by National Institutes of Health Award R01 AR066667-01 (to D.P. and L.J.B.) and NSF Award DMR-1352299 (to D.G.). E.F. is grateful for the financial support of an NSF graduate research fellowship. This work was made possible by the Cornell Chemistry NMR facility and NSF-MRI (Grant CHE-1531632-PI: Aye) for NMR instrumentation support at Cornell University. This work made use of the Cornell Center for Materials Research Shared Facilities, which are supported through the NSF MRSEC program (DMR-1719875).
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Gourdon, Professor Delphine
• Authors: Sun, Z., Feeney, E., Guan, Y., Cook, S. G., Gourdon, D., Bonassar, L. J., and Putnam, D.
• College/School: College of Science and Engineering > School of Engineering > Biomedical Engineering
• Journal Name: Proceedings of the National Academy of Sciences of the United States of America
• Publisher: National Academy of Sciences
• ISSN: 0027-8424
• ISSN (Online): 1091-6490
• Published Online: 04 June 2019
• Copyright Holders: Copyright © 2019 National Academy of Sciences
• First Published: First published in Proceedings of the National Academy of Sciences of the United States of America 116(25):12437-12441
• Publisher Policy: Reproduced in accordance with the copyright policy of the publisher