Additive manufacturing of cell-loaded alginate enriched with alkaline phosphatase for bone tissue engineering application

Rainer Detsch 1 , Bapi Sarker 1 , Tobias Zehnder 1 , Aldo R. Boccaccini 1 , and Timothy E.L. Douglas 2
  • 1 Institute of Biomaterials, Department of Materials Science and Engineering, University of Erlangen-Nuremberg, Cauerstr. 6, 91058 Erlangen, Germany
  • 2 Polymer Chemistry and Biomaterials (PBM) Group, Department of Organic Chemistry, Ghent University, Krijgslaan 281 S4, 9000 Ghent, Belgium
Rainer Detsch, Bapi Sarker, Tobias Zehnder, Aldo R. Boccaccini and Timothy E.L. Douglas


Hydrogels are gaining interest as scaffolds for bone tissue regeneration due to ease of incorporation of cells and biological molecules such as enzymes. Mineralization of hydrogels, desirable for bone tissue regeneration applications, may be achieved enzymatically by incorporation of alkaline phosphatase (ALP). Additive manufacturing techniques such as bioplotting enable the layer-by-layer creation of three-dimensional hydrogel scaffolds with highly defined geometry and internal architecture. In this study, we present a novel method to produce macroporous hydrogel scaffolds in combination with cell-loaded capsule-containing struts by 3D bioplotting. This approach enables loading of the capsules and strut phases with different cells and/or bioactive substances and hence makes compartmentalization within a scaffold possible. 3D porous alginate scaffolds enriched with ALP and MG-63 osteoblast-like cells were produced by bioplotting struts of alginate which were loaded with pre-fabricated alginate capsules. Two combinations were compared, namely ALP in the struts and cells in the capsules and vice-versa. Both combinations were cytocompatible for cells and mineralization of scaffolds could be detected in both cases, according to an OsteoImage staining. ALP had no adverse effect on cytocompatibility and enhanced mitochondrial activity.

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