Polarized light micrographs.

<p>Images of in vivo bone formation in the silk (B,b), BG/silk (D,d) and MBG/silk (F,f) groups at 4 weeks, with the same field of silk (A,a), BG/silk (C,c) and MBG/silk (E,e) groups shown in H&E staining. Scaffolds are bright white in dark field, and mature collagen fibers are red or yellow. More mature collagen matrix appears in MBG/silk group. Lower magnification (x100; A-F; bar=200 µm); higher magnification (x400; a-f; Bar=50µm).