Biomineralization foci can be isolated from total cell layers by laser capture microscopy. A and B, UMR-106-01 osteoblastic cells were cultured in serum-depleted conditions (BSA), or C, the presence of serum (FBS). Cultures were stained with Alizarin red S to detect hydroxyapatite crystals. B, both conditions failed to mineralize in the absence of BGP. Arrows point to mineralized BMF (A and C). Scale bar: 500 μm. D–F, laser capture microscopy of Alizarin red S stained BMF from UMR-106-01 culture. Arrows refer to the same BMF structures in all panels. D, microscopic view of field to be laser-captured. E, appearance of the residual cell layer left behind after laser dissection of mineralized BMF. F, purified BMF temporarily affixed to the “cap” used for laser capture. Scale bar: 25 μm. (Reproduced with permission of the J. of Biological Chemistry).