Static versus vacuum cell seeding on high and low porosity ceramic scaffolds

An adequate cell seeding technique is essential for effective bone regeneration on cell seeded constructs of porous tricalcium phosphates. In previous studies, dynamic cell seeding, in which an external force is applied to seed cells on a biomaterial, resulted in more homogeneous cell seeding in low porosity scaffolds than static seeding. The optimal cell seeding technique for high porosity scaffolds has not been defined yet. Human mesenchymal stem cells were isolated from bone marrow and characterized. The cells were seeded on low porosity (45%) and high porosity (90%) tricalcium phosphate scaffolds using a static and a vacuum seeding technique. LIVE/DEAD® staining of the cell-scaffold complexes followed by confocal laser scanning microscopy was used to measure cell proliferation, cell distribution and cell viability one, three and seven days after seeding. Cell proliferation was also quantified using a DNA quantification assay. Neither static nor vacuum seeding resulted in homogeneous cell seeding on both low and high porosity scaffolds. Cell density was lower on the inside than on the outside of the scaffolds. On low porosity scaffolds, the vacuum method yielded the highest numbers of cells compared to the static method. Low porosity scaffolds were seeded most homogeneously using the static seeding method. Seven days after seeding, numbers of adherent cells were comparable for both scaffold types and independent of the cell seeding technique used. In conclusion, on high porosity scaffolds, static seeding results in more homogeneous cell seeding and it is easier to use than a vacuum seeding technique.