Journal of Sol-Gel Science and Technology

, Volume 83, Issue 1, pp 143–154 | Cite as

Effects of curing and organic content on bioactivity and mechanical properties of hybrid sol–gel glass scaffolds made by indirect rapid prototyping

  • Stephan Hendrikx
  • Dzmitry Kuzmenka
  • Roberto Köferstein
  • Tobias Flath
  • Hans Uhlig
  • Dirk Enke
  • F. Peter Schulze
  • Michael C. Hacker
  • Michaela Schulz-SiegmundEmail author
Original Paper: Sol-gel and hybrid materials for biological and health (medical) applications


We employed indirect rapid prototyping templating to fabricate bioactive and macroporous scaffolds for bone regeneration. This templating technique utilizes lost molds made of polycaprolactone by fused deposition modeling, in which the organic/ inorganic hybrid silica sol was filled and cured. Finally, the molds were dissolved and extracted, and the remaining macroporous hybrid glass constructs were recovered. The hybrid glass scaffolds offered a fully interconnected pore structure with 63–72% porosity measured by N2-pycnometry and Hg-intrusion. In bioactive sol–gel glasses one issue is the insufficient and inhomogeneous incorporation of calcium (II) ions. To address this problem we varied the curing conditions and tested the effect of the organic crosslinker on calcium retention. We strengthened the silica network by covalent crosslinking with trimethylolpropane ethoxylate which was functionalized with 3-(triethoxysilyl)propyl isocyanate. Those scaffolds showed compressive yield strengths of up to 12.7 MPa and compressive moduli between 18 and 288 MPa. Energy dispersive X-ray spectroscopy showed that a crosslinker content of 60% in the hybrids resulted in a homogeneous calcium distribution in the glass, in contrast to 40% where we found a layer of CaCl2 on the scaffold surface. The materials exhibited bioactivity in simulated body fluid which was monitored by scanning electron microscopy and X-ray powder diffraction.

Graphical Abstract

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Binary Ternary Mechanical testing Bioactive Class-II hybrid Indirect rapid prototyping 



The authors thank Prof. Dr.-Ing. Bernhard Rieger (Department of Mechanical and Energy Engineering, HTWK Leipzig, Germany) for access to the compression testing equipment, Jörg Lenzner (Department of Experimental and Semiconductor Physics, Leipzig University) for access to SEM and EDX. The authors would also like to thank the Saxon Ministry for Science and Arts (Grant no: 4-7531.60/64/18) and the German Research Council (DFG SFB/Transregio 67 A1) for financial support.

Compliance with ethical standards

Conflict of interest

The authors declare that they have no competing interests.


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Copyright information

© Springer Science+Business Media New York 2017

Authors and Affiliations

  • Stephan Hendrikx
    • 1
  • Dzmitry Kuzmenka
    • 1
  • Roberto Köferstein
    • 2
  • Tobias Flath
    • 3
  • Hans Uhlig
    • 4
  • Dirk Enke
    • 5
  • F. Peter Schulze
    • 3
  • Michael C. Hacker
    • 1
  • Michaela Schulz-Siegmund
    • 1
    Email author
  1. 1.Pharmaceutical Technology, Institute of PharmacyLeipzig UniversityLeipzigGermany
  2. 2.Inorganic Chemistry, Institute of ChemistryMartin-Luther-University Halle-WittenbergHalle (Saale)Germany
  3. 3.Department of Mechanical and Energy EngineeringLeipzig University of Applied SciencesLeipzigGermany
  4. 4.Institute of Non-Classical Chemistry e. V. at the Leipzig UniversityLeipzigGermany
  5. 5.Institute for Chemical TechnologyLeipzig UniversityLeipzigGermany

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