title: Preparation of recombinant human bone morphogenetic protein-2 loaded dextran-based microspheres and their characteristics.
abstract: OBJECTIVE
  To prepare new pharmaceutical forms with sustained delivery properties of recombinant human bone morphogenetic protein-2 (rhBMP2) for tissue engineering and guided tissue regeneration (GTR) use.
  
  
  METHODS
  rhBMP2-loaded dextran-based hydrogel microspheres (rhBMP2-MPs), which aimed to keep rhBMP2 bioactivity and to achieve long-term sustained release of rhBMP2, were prepared by double-phase emulsified condensation polymerization. The physical, chemical performances and biological characteristics of those microspheres were studied both in vitro and in vivo.
  
  
  RESULTS
  The microspheres' average diameter was 30.33+/-4.32 microm with 75.4% ranging from 20 microm to 40 microm and the drug loading and encapsulation efficiency were 7.82% and 82.25%, respectively. The rhBMP2-releasing profiles in vitro showed that rhBMP2 release could be maintained more than 10 d. The rhBMP2-MPs, with good swelling and biodegradation behavior, could be kept for 6 months at below 4 degree without significant characteristic change or bioactivity loss. Cytology studies showed that rhBMP2-MPs could promote the proliferation of periodontal ligament cells (PDLCs) approximately 10 d, while the bioactivity of concentrated rhBMP2 solution could keep no more than 3 d. Scanning electron microscope showed that rhBMP2-MPs could be enchased into the porous structure of calcium phosphate ceremic (CPC) and the eugonic growth of PDLCs in CPC/rhBMP2-MPs scaffolds. Animal experiments indicated that using CPC/rhBMP2-MPs scaffolds could gain more periodontal tissue regeneration than using rhBMP2 compound firsthand with CPC (CPC/rhBMP2).
  
  
  CONCLUSIONS
  By encapsulating rhBMP2 into dextran-based microspheres, a small quantity of rhBMP2 could achieve equivalent effects to the concentrated rhBMP2 solution and at the same time, could prolong rhBMP2 retention both in vitro and in vivo.
authors.affiliation: Center for Tissue Engineering, College of Stomatology, the Fourth Military Medical University, Xi-an 710032, China.
authors.forename: Fa-ming
authors.initials: FM
authors.lastname: Chen
authors.forename: Zhi-fen
authors.initials: ZF
authors.lastname: Wu
authors.forename: Qin-tao
authors.initials: QT
authors.lastname: Wang
authors.forename: Hong
authors.initials: H
authors.lastname: Wu
authors.forename: Yong-jie
authors.initials: YJ
authors.lastname: Zhang
authors.forename: Xin
authors.initials: X
authors.lastname: Nie
authors.forename: Yan
authors.initials: Y
authors.lastname: Jin
mesh_terms: D000818:Animals; D001673:Biodegradation, Environmental; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins / Q000008:administration & dosage* / Q000494:pharmacology; D049109:Cell Proliferation / Q000187:drug effects; D003692:Delayed-Action Preparations; D003911:Dextrans; D004285:Dogs; D005260:Female; D008863:Microspheres; D010316:Particle Size; D010513:Periodontal Ligament / Q000166:cytology* / Q000187:drug effects; D011994:Recombinant Proteins / Q000008:administration & dosage / Q000494:pharmacology; D013678:Technology, Pharmaceutical / Q000379:methods*; D016212:Transforming Growth Factor beta / Q000008:administration & dosage* / Q000494:pharmacology
chemical_list: C525718:BMP2 protein, human; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins; D003692:Delayed-Action Preparations; D003911:Dextrans; D011994:Recombinant Proteins; D016212:Transforming Growth Factor beta