Chinese Journal of Tissue Engineering Research ›› 2018, Vol. 22 ›› Issue (2): 210-215.doi: 10.3969/j.issn.2095-4344.0008

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Recombinant human bone morphogenetic protein 2/poly(lactic-co-glycolic acid) copolymer microspheres with different particle sizes: preparation and release performance in vivo and in vitro  

Bao Yu-cheng1, Wang Yong1, Zhang Wen-long1, Xie Yi1, Yu Mei-li2
  

  1. 1Tianjin Haihe Hospital, Tianjin 300350, China; 2Third Central Hospital of Tianjin, Tianjin Key Laboratory of Artificial Cells, Tianjin 300170, China
  • Received:2017-08-01 Online:2018-01-18 Published:2018-01-18
  • Contact: Wang Yong, Senior engineer, Tianjin Haihe Hospital, Tianjin 300350, China Yu Mei-li, Researcher, Third Central Hospital of Tianjin, Tianjin Key Laboratory of Artificial Cells, Tianjin 300170, China
  • About author:Bao Yu-cheng, Associate chief physician, Tianjin Haihe Hospital, Tianjin 300350, China
  • Supported by:
     Jinnan Science and Technology Foundation of Tianjin, No. 2015001

Abstract:

BACKGROUND: The technology of biodegradable materials covering growth factors can be used to make sustained-release microspheres, which provides the feasibility for the efficient utilization of growth factors.
OBJECTIVE: To prepare nano/micron-sized spheres using recombinant human bone morphogenetic protein 2/poly(lactic-co-glycolic acid) (rhBMP-2/PLGA) copolymer and to compare their release behaviors by in vivo and in vitro release experiments.
METHODS: The rhBMP-2/PLGA nano/micron-sized spheres were prepared by emulsion solvent evaporation method to control the rate of pulp mixing. (1) In vitro release experiment: Prepared nano/micron-sized spheres were dissolved in PBS for 70 days, and then ELISA method was used to detect the rhBMP-2 concentration in the supernatant at different time. (2) In vivo release experiment: Forty-four New Zealand rabbits were divided into two groups, and rhBMP-2/PLGA nano/micron-sized spheres were respectively implanted into trochanteric defects. The concentration of rhBMP-2 in the defect site was detected by ELISA within 70 days after implantation.
RESULTS AND CONCLUSION: In vitro sustained release experiment: There was a sudden release of nanospheres in the former 3 days, and the cumulative release nearly reached 41%, followed by a steady and slow release, and then the cumulative release was up to approximately 83% at 70 days. The initial release of micron-sized spheres was less than that of nanospheres, and the cumulative release was about 20% within the former 3 days and reached to 70% at 70 days. In vivo sustained release test: There was a sudden release of the nanospheres, the cumulative release was nearly 35%, followed by a steady and slow release, and then the cumulative release was up to approximately 72% at 70 days. The initial release of micron-sized spheres was less than that of nanospheres, and the cumulative release was about 21% in the former 3 days and increased to about 63% at 70 days. In both in vivo and in vitro release experiments, the release duration of micron-sized spheres was longer than that of nanospheres in the former 3 days. To conclude, the release time of rhBMP-2/PLGA micron-sized spheres fulfills the need of bone growth cycle, therefore, rhBMP-2/PLGA micron-sized spheres are more favorable than rhBMP-2/PLGA nanospheres for bone defect repair in clinical practice.

Key words: Bone Morphogenetic Proteins, Microspheres, Drug Delivery Systems, Tissue Engineering

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