Ultrathin sP(EO-stat-PO) hydrogel coatings are biocompatible and preserve functionality of surface bound growth factors in vivo

  • Carl Neuerburg
  • Stefan Recknagel
  • Jörg Fiedler
  • Jürgen Groll
  • Martin Moeller
  • Kristina Bruellhoff
  • Heiko Reichel
  • Anita Ignatius
  • Rolf E. BrennerEmail author


Hydrogel coatings prepared from reactive star shaped polyethylene oxide based prepolymers (NCO-sP(EO-stat-PO)) minimize unspecific protein adsorption in vitro, while proteins immobilized on NCO-sP(EO-stat-PO) coatings retain their structure and biological function. The aim of the present study was to assess biocompatibility and the effect on early osseointegrative properties of a NCO-sP(EO-stat-PO) coating with additional RGD-peptides and augmentation with bone morphogenetic protein-4 (BMP) used on a medical grade high-density polyethylene (HDPE) base under in vivo circumstances. For testing of biocompatibility dishes with large amounts of bulk NCO-sP(EO-stat-PO) were implanted subcutaneously into 14 Wistar rats. In a second set-up functionalization of implants with ultrathin surface layers by coating ammonia-plasma treated HDPE with NCO-sP(EO-stat-PO), functionalization with linear RGD-peptides, and augmentation with RGD and BMP-4 was analyzed. Therefore, implants were placed subcutaneously in the paravertebral tissue and transcortically in the distal femur of another 14 Wistar rats. Both tests revealed no signs of enhanced inflammation of the surrounding tissue analyzed by CD68, IL-1ß-/TNF-α-antibody staining, nor systemic toxic reactions according to histological analysis of various organs. The mean thickness of the fibrous tissue surrounding the femoral implants was highest in native HDPE-implants and tended to be lower in all NCO-sP(EO-stat-PO) modified implants. Micro-CT analysis revealed a significant increase of peri-implant bone volume in RGD/BMP-4 coated samples. These results demonstrate that even very low amounts of surface bound growth factors do have significant effects when immobilized in an environment that retains their biological function. Hence, NCO-sP(EO-stat-PO)-coatings could offer an attractive platform to improve integration of orthopedic implants.


Bone Morphogenetic Protein Tramadol HDPE Protein Adsorption Hydrogel Film 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.



The authors wish to thank Aesculap (Tuttlingen, Germany) for providing the high density polyethylene carrier implants. Also we would like to thank Nadine Jansen, Sarah Krauthausen and Giovanni Ravalli for excellent technical assistance.


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Copyright information

© Springer Science+Business Media New York 2013

Authors and Affiliations

  • Carl Neuerburg
    • 1
    • 6
  • Stefan Recknagel
    • 2
  • Jörg Fiedler
    • 3
  • Jürgen Groll
    • 4
    • 5
  • Martin Moeller
    • 4
  • Kristina Bruellhoff
    • 4
  • Heiko Reichel
    • 1
  • Anita Ignatius
    • 2
  • Rolf E. Brenner
    • 3
    Email author
  1. 1.Department of OrthopaedicsUniversity of UlmUlmGermany
  2. 2.Institute of Orthopaedic Research and BiomechanicsUniversity of UlmUlmGermany
  3. 3.Division for Biochemistry of Joint and Connective Tissue Diseases, Department of OrthopaedicsUniversity of UlmUlmGermany
  4. 4.DWI e.V. and Institute of Technical and Macromolecular ChemistryRWTH Aachen UniversityAachenGermany
  5. 5.Department of Functional Materials in Medicine and DentistryUniversity Hospital WürzburgWürzburgGermany
  6. 6.Experimental Surgery and Regenerative Medicine, Department of SurgeryLudwig-Maximilians-UniversityMunichGermany

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