Size matters: effects of PLGA-microsphere size in injectable CPC/PLGA on bone formation

Authors

  • Hongbing Liao,

    1. Department of Biomaterials, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
    2. College of Stomatology, Guangxi Medical University, Nanning, People's Republic of China
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    • These authors contributed equally to this study.

  • Rosa P. Félix Lanao,

    1. Department of Biomaterials, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
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    • These authors contributed equally to this study.

  • Jeroen J. J. P. van den Beucken,

    1. Department of Biomaterials, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
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  • Nuo Zhou,

    1. College of Stomatology, Guangxi Medical University, Nanning, People's Republic of China
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  • Sanne K. Both,

    1. Department of Biomaterials, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
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  • Joop G. C. Wolke,

    1. Department of Biomaterials, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
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  • John A. Jansen

    Corresponding author
    1. Department of Biomaterials, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
    • Correspondence to: John A. Jansen, Department of Biomaterials, 309 Radboud University Nijmegen Medical Centre, PO Box 9101, 6500 HB Nijmegen, The Netherlands. E-mail: J.Jansen@dent.umcn.nl

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Abstract

The aim of this study was to evaluate the effect of PLGA microsphere dimensions on bone formation after injection of calcium phosphate cement (CPC)/PLGA in a guinea pig tibial intramedullarly model. To this end, injectable CPC/PLGA formulations were prepared using PLGA microspheres with either a small (~25 µm) or large (~100 µm) diameter, which were incorporated at a 20:80 ratio (wt%) within apatite CPC. Both CPC/PLGA formulations were injected into a marrow-ablated tibial intramedullary cavity and, after an implantation period of 12 weeks, histology and histomorphometry were used to address bone formation. The results demonstrated bone ingrowth throughout the entire scaffold material for both CPC/PLGA formulations upon PLGA microsphere degradation. More importantly, bone formation within the CPC matrix was > two-fold higher for CPC-PLGA with 25 µm PLGA microspheres. Additionally, the pattern of bone and marrow formation showed distinct differences related to PLGA microsphere dimension. In general, this study demonstrates that PLGA microsphere dimensions of ~25 µm, leading to pores of ~25 µm within CPC, are sufficient for bone ingrowth and allow substantial bone formation. Further, the results demonstrate that PLGA microsphere dimensions provide a tool to control bone formation for injectable CPC/PLGA bone substitutes. Copyright © 2013 John Wiley & Sons, Ltd.

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