Histological analysis of a defect filled with PLLA/BMP-2.

<p>(<b>a</b>) New bone ossicle with active osteoblasts on the upper right edge and lining cells on the opposite edge in a defect implanted with PLLA/BMP-2 after 8 weeks (Hematoxylin-Eosin, BF). (<b>b</b>) New bone formation in a defect filled with PLLA/BMP-2 after 12 weeks, viewed under visible light, showing the remains of PLLA nanofibers (Masson-Goldner, BF). (<b>c</b>) The same micrograph as in ‘b’ under polarized light microscopy, revealing the full extent of bone incorporation through the nanofiber scaffold as well as some loose collagen fibers at the top (Masson-Goldner, POL).