Figure 2
![Figure 2](http://media.springernature.com/full/springer-static/image/art%3A10.1186%2Fs40824-015-0027-1/MediaObjects/40824_2015_27_Fig2_HTML.gif)
Scanning electron microscopy images. A and B shows the cross section and longitudinal section of the silk scaffold respectively prior to the cell culture. Porous, interconnected structure can be observed, ×100 magnification. C and D show the cross section and longitudinal section of the silk scaffold respectively, following the cell culture, ×400 magnification. Arrows represent spreading of the cells with secreted extracellular matrix on the silk fibroin. Arrowheads represent nHA crystals on silk fibroin.