Nanofibrous hollow microspheres self-assembled from star-shaped polymers as injectable cell carriers for knee repair

ABSTRACT To repair complexly shaped tissue defects, an injectable cell carrier is desirable to achieve an accurate fit and to minimize surgical intervention. However, the injectable carriers

available at present have limitations, and are not used clinically for cartilage regeneration. Here, we report nanofibrous hollow microspheres self-assembled from star-shaped biodegradable

polymers as an injectable cell carrier. The nanofibrous hollow microspheres, integrating the extracellular-matrix-mimicking architecture with a highly porous injectable form, were shown to

efficiently accommodate cells and enhance cartilage regeneration, compared with control microspheres. The nanofibrous hollow microspheres also supported a significantly larger amount of, and

higher-quality, cartilage regeneration than the chondrocytes-alone group in an ectopic implantation model. In a critical-size rabbit osteochondral defect-repair model, the nanofibrous

hollow microspheres/chondrocytes group achieved substantially better cartilage repair than the chondrocytes-alone group that simulates the clinically available autologous chondrocyte

implantation procedure. These results indicate that the nanofibrous hollow microspheres are an excellent injectable cell carrier for cartilage regeneration. Access through your institution

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Am._ 68, 1017–1035 (1986). Google Scholar  Download references ACKNOWLEDGEMENTS The authors would like to acknowledge the financial support from the National Institutes of Health (Research

Grants DE015384 and DE017689: P.X.M.). The authors would also like to acknowledge the assistance from J. Hu in the animal experiments. AUTHOR INFORMATION Author notes * Xiaohua Liu and

Xiaobing Jin: These authors contributed equally to this work AUTHORS AND AFFILIATIONS * Department of Biologic and Materials Sciences, 1011 North University Ave., Room 2211, University of

Michigan, Ann Arbor, Michigan 48109-1078, USA Xiaohua Liu, Xiaobing Jin & Peter X. Ma * Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan 48109-1078, USA

Peter X. Ma * Macromolecular Science and Engineering Center, University of Michigan, Ann Arbor, Michigan 48109-1078, USA Peter X. Ma * Department of Materials Science and Engineering,

University of Michigan, Ann Arbor, Michigan 48109-1078, USA Peter X. Ma Authors * Xiaohua Liu View author publications You can also search for this author inPubMed Google Scholar * Xiaobing

Jin View author publications You can also search for this author inPubMed Google Scholar * Peter X. Ma View author publications You can also search for this author inPubMed Google Scholar

CONTRIBUTIONS X.L. and X.J. contributed overall equally to the experimental work. X.L. carried out the polymer synthesis, fabrication of microspheres and structural characterization. X.J.

carried out the cell culture, animal studies and tissue analyses. P.X.M. was responsible for the overall project design and manuscript organization. All authors contributed to the scientific

planning, data analysis and interpretation. CORRESPONDING AUTHOR Correspondence to Peter X. Ma. ETHICS DECLARATIONS COMPETING INTERESTS The authors declare no competing financial interests.

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hollow microspheres self-assembled from star-shaped polymers as injectable cell carriers for knee repair. _Nature Mater_ 10, 398–406 (2011). https://doi.org/10.1038/nmat2999 Download

citation * Received: 19 December 2009 * Accepted: 01 March 2011 * Published: 17 April 2011 * Issue Date: May 2011 * DOI: https://doi.org/10.1038/nmat2999 SHARE THIS ARTICLE Anyone you share

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