EFFECT OF POLYMERIC SCAFFOLD STRUCTURE ON OSTEOGENIC DIFFERENTIATION OF HUMAN BONE MARROW STROMAL CELLS
Girish Kumar1, Marian F. Young2, Carl G. Simon, Jr.1
1Polymers Division, National Institute of Standards and Technology, Gaithersburg MD 20899, USA
2National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda MD 20892, USA
Structural properties of polymeric scaffolds play a key role in bone formation in vitro and in vivo. These properties depend primarily on the chemical nature and the fabrication process of biomaterial. There are many well established protocols for fabricating scaffolds that have been tested for bone tissue engineering applications. These approaches afford control over scaffold topology, structure and pore geometry. In addition, much work has demonstrated that cell differentiation is sensitive to topology at sizes ranging from nano- to micro- to macroscale.
In this study we compare scaffold architecture for osteogenic differentiation of human bone marrow stromal cells (hBMSCs). We prepared scaffolds of PCL (poly(ε-caprolactone) using various fabrication techniques including “salt leaching”, “gas foaming”, “phase-separation” and “electro-spinning”. For controls, we used tissue culture polystyrene and a spun-coat PCL films. Scaffolds prepared using these techniques not only have different physical architecture but they also have dissimilar topology. We evaluated hBMSC proliferation, differentiation and osteogenesis on these substrates at different time points out to 2 months of culture. We found that scaffold structure had large effects on hBMSC response and the nanofiber scaffolds were best for inducing osteogenesis in the absence of osteogenic supplements (dexamethasone, ascorbic acid, beta-glycerophosphate).