No abstract

For tissue engineering of critical size bone grafts, nanocomposites are getting more and more attractive due to their controllable physical and biological properties. We report in vitro and in vivo behaviour of an electrospun nanocomposite based on poly-lactic-co-glycolic acid and amorphous calcium phosphate nanoparticles (PLGA/a-CaP) seeded with human adipose-derived stem cells (ASC) compared to PLGA. Major findings were that cell attachment, three-dimensional ingrowth and proliferation were very good on both materials. Cell morphology changed from a spindle-shaped fibroblast-like form to a more roundish type when ASC were seeded on PLGA, while they retained their morphology on PLGA/aCaP. Moreover, we found ASC differentiation to a phenotype committed towards osteogenesis when a-CaP nanoparticles were suspended in normal culture medium without any osteogenic supplements, which renders a-CaP nanoparticles an interesting osteoinductive component for the synthesis of other nanocomposites than PLGA/a-CaP. Finally, electrospun PLGA/a-CaP scaffold architecture is suitable for a rapid and homogenous vascularisation confirmed by a complete penetration by avian vessels from the chick chorioallantoic membrane (CAM) within one week.

Tissue engineering of bone grafts was addressed in a critical-sized model on the chick chorioallantoic membrane model, using DegraPol(®) foam as scaffold material. The scaffolds were seeded with cultures of human osteoblasts and human endothelial cells, respectively, or with a co-culture of the two cell types (control: no cells). In vitro samples (7 days cultivation) and ex vivo chorioallantoic membrane model samples at incubation day 15 were analyzed by high-field magnetic resonance imaging (MRI) and histology. The co-culture system performed best with respect to perfusion, as assessed by contrast-enhanced MRI using gadolinium-diethylene-triamine-pentaacetic acid (DTPA). The scaffold seeded by the co-culture supported an increased vascular ingrowth, which was confirmed by histological analysis. DegraPol foam is a suitable scaffold for bone tissue engineering and the MRI technique allows for nondestructive and quantitative assessment of perfusion capability during early stages of bone forming constructs.

No abstract

No abstract