Fig. 2

Confocal laser microscopy images (top and side view) of osteoclasts cultured on uncoated (a, c, e) and CoCaP-coated BiominCol membranes (b, d, f), at 7, 14 and 21 days. At 7 days, multi-nucleated cells were visible on uncoated BiominCol, with the central cell showing a thick actin structure (podosome belt - dashed circle). CoCaP-coated BiominCol membrane also exhibited multi-nucleated cells at this point. No TRAP+ cells were observed on either substrate. At 14 days, several TRAP+ multi-nucleated large cells were observed on both surfaces. High intensity actin structures were observed close to the surface of the material, but they do not appear to be actin rings. At 21 days, actin structures resembling actin rings were observed on some osteoclasts on CoCaP-coated BiominCol membranes (dashed circle and arrowheads), but not on the uncoated ones. Dashed lines in the side views represent the surface of the membrane. For all images: scale bar is 50 μm, actin in red, nuclei in blue, and TRAP in green