Hyaluronan-based heparin-incorporated hydrogels for generation of axially vascularized bioartificial bone tissues: in vitro and in vivo evaluation in a PLDLLA–TCP–PCL-composite system

  • Subha N. Rath
  • Galyna Pryymachuk
  • Oliver A. Bleiziffer
  • Christopher X. F. Lam
  • Andreas Arkudas
  • Saey T. B. Ho
  • Justus P. Beier
  • Raymund E. Horch
  • Dietmar W. Hutmacher
  • Ulrich Kneser


Smart matrices are required in bone tissue-engineered grafts that provide an optimal environment for cells and retain osteo-inductive factors for sustained biological activity. We hypothesized that a slow-degrading heparin-incorporated hyaluronan (HA) hydrogel can preserve BMP-2; while an arterio–venous (A–V) loop can support axial vascularization to provide nutrition for a bio-artificial bone graft. HA was evaluated for osteoblast growth and BMP-2 release. Porous PLDLLA–TCP–PCL scaffolds were produced by rapid prototyping technology and applied in vivo along with HA-hydrogel, loaded with either primary osteoblasts or BMP-2. A microsurgically created A–V loop was placed around the scaffold, encased in an isolation chamber in Lewis rats. HA-hydrogel supported growth of osteoblasts over 8 weeks and allowed sustained release of BMP-2 over 35 days. The A–V loop provided an angiogenic stimulus with the formation of vascularized tissue in the scaffolds. Bone-specific genes were detected by real time RT-PCR after 8 weeks. However, no significant amount of bone was observed histologically. The heterotopic isolation chamber in combination with absent biomechanical stimulation might explain the insufficient bone formation despite adequate expression of bone-related genes. Optimization of the interplay of osteogenic cells and osteo-inductive factors might eventually generate sufficient amounts of axially vascularized bone grafts for reconstructive surgery.



Hyaluronic acid/hyaluronan hydrogel


Bone morphogenetic protein


Computerized tomography








β-Tri-calcium phosphate



This study was supported by research grants from the Deutsche Forschungsgemeinschaft (DFG) (KN 578/2-1) and the Xue Hong and Hans Georg Geis Foundation. The authors thank Dr. Andreas Hess, Institute of Experimental and Clinical Pharmacology and Toxicology for helping in micro-CT scanning and Prof. Peter Greil and Mr. Peter Reinhard for production of the Teflon chambers.


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Copyright information

© Springer Science+Business Media, LLC 2011

Authors and Affiliations

  • Subha N. Rath
    • 1
    • 2
  • Galyna Pryymachuk
    • 1
  • Oliver A. Bleiziffer
    • 1
  • Christopher X. F. Lam
    • 2
  • Andreas Arkudas
    • 1
  • Saey T. B. Ho
    • 3
  • Justus P. Beier
    • 1
  • Raymund E. Horch
    • 1
  • Dietmar W. Hutmacher
    • 4
  • Ulrich Kneser
    • 1
  1. 1.Department of Plastic and Hand SurgeryUniversity of Erlangen Medical CenterErlangenGermany
  2. 2.Division of BioengineeringNational University of SingaporeSingaporeSingapore
  3. 3.Graduate Programme in Bioengineering, Yong Loo Lin School of MedicineNational University of SingaporeSingaporeSingapore
  4. 4.Faculty of Engineering, Faculty of Science, Institute of Health and Biomedical InnovationQueensland University of TechnologyBrisbaneAustralia

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