Fig. 1
![Fig. 1](http://media.springernature.com/full/springer-static/image/art%3A10.1186%2Fs40064-016-2492-y/MediaObjects/40064_2016_2492_Fig1_HTML.jpg)
The TEM images of different apatites. a nano-hydroxyapatite (NAP), b micro-hydroxyapatite (MAP), c ordinary particle size of apatite (OAP)
The TEM images of different apatites. a nano-hydroxyapatite (NAP), b micro-hydroxyapatite (MAP), c ordinary particle size of apatite (OAP)