Struts and Capsules

3D-printing of Cell-loaded Alginate Capsules suspended in Hydrogel

Printable biomaterials can benefit from complex compositions: The release of drugs or cell  growth have to be controlled after printing. A group from the Friedrich-Alexander University in Erlangen added prefabricated capsules enriched with cells to hydrogel before printing.

The GeSiM BioScaffolder was part of this study. It presents 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.

Light microscopy images of cell-loaded alginate capsules in ALP-loaded alginate struts immediately after fabrication. The free space in the center of the image is a macropore.

Light microscopy images of cell-loaded alginate capsules in ALP-loaded alginate struts immediately after fabrication. The free
space in the center of the image is a macropore.

Fluorescence microscopy image after 10 days of culture and OsteoImage®, DAPI and Vybrant staining capsules loaded with ALP. Green: calcium phosphate. Blue: cell nuclei. Red: cell body. Scale bars: a = 200 µm, b = 500 µm

Fluorescence microscopy image after 10 days of culture and OsteoImage®, DAPI and
Vybrant staining capsules loaded with ALP. Green: calcium phosphate. Blue: cell nuclei. Red: cell body. Scale bars: a = 200 µm, b = 500 µm

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

The goal was to produce scaffolds for possible applications in bone tissue engineering consisting of alginate struts containing alginate capsules enriched with MG-63 osteoblast-like cells and ALP (alkaline phosphatase). 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.

Different components desirable for bone regeneration, e.g., cells and bioactive proteins, can be incorporated both in the capsules and struts. This enables compartmentalization of components, which facilitates greater flexibility in modification of the scaffold.

Institute of Biomaterials Erlangen

Institute of Biomaterials Erlangen


Rainer Detsch, Bapi Sarker, Tobias Zehnder, Aldo R. Boccaccini and Timothy E.L. Douglas:
Additive manufacturing of cell-loaded alginate enriched with alkaline phosphatase for bone tissue engineering application. De Gruyter, BioNanoMat 2014; 15(3-4): 79–87