Bone tissue engineering is one of the fastest growing branches in modern bioscience. New methods are being developed to achieve higher grades of mineral deposition by osteogenically inducted mesenchymal stem cells. In addition to well established monolayer cell culture models, 3D cell cultures for stem cell-based osteogenic differentiation have become increasingly attractive to promote Within the present study, we evaluated whether this promising new method, using 99mTc-hydroxydiphosphonate (99mTc-HDP), can be used to quantify the amount of newly formed extracellular HA in a 3D cell culture model. Highly porous collagen type II scaffolds were seeded with 1 × 106 human mesenchymal stem cells (hMSCs; n = 6) and cultured for 21 days in osteogenic media (group A – osteogenic (OSM) group) and in parallel in standard media (group B – negative control (CNTRL) group). After incubation with 99mTc-HDP, the tracer uptake, reflected by the amount of emitted gamma counts, was measured.Objectives
Methods
One of the most challenging problems in osteogenic 3D-tissue engineering is, to quantify the amount of new hydroxylapatite deposition. 18F-NaF-Labeling is a new, high-sensitive method to proof and quantify the osteogenic potential of hMSCs in an in vitro 3D-model.
18F-labeled sodium fluorine was the first widely used agent for skeletal scintigraphy in the 1960s. 18F-NaF is rapidly exchanged for hydroxylgroups of the hydroxylapatite, covalently binding to the surface of new bone, which results in the formation of fluoroapatite. Three dimensional scaffolds are used to favor osteogenic differentiation of precursor cells. Cell-loaded scaffolds are investigated for their healing potential of critical size bone defects. Assessing the osteogenic potential of MSCs in 3D-in vitro cultures is of major interest in tissue engineering in order to maximise bone formation in vitro and in vivo. One of the most challenging problems is, to quantify directly the amount of new hydroxylapatite deposition without destroying the evaluated cell-loaded scaffold. Within this abstract, we present a novel, non-destructive, high-sensitive method to quantify the amount of local hydroxylapatite deposition in 3D-cultures using 18F-NaF.Summary Statement
Introduction
