Fig. 1
![Fig. 1](http://media.springernature.com/full/springer-static/image/art%3A10.1186%2Fs13018-020-02177-5/MediaObjects/13018_2020_2177_Fig1_HTML.png)
The surface topography, surface adhesion, and ingredients were identified in HA and NGF-CS/HA coatings. a The surface topography was observed by applying SEM in HA (n = 3) and NGF-CS/HA (n = 3) coatings. Magnification, × 2000; magnification, × 10000. b The scratch in NGF-CS/HA composite coatings were observed by SEM. c The ingredients were analyzed through XRD spectrums using the Origin7.0 software in HA (n = 3) and NGF-CS/HA (n = 3) coatings