Fig. 1.

Characteristics of PDA-based nanoparticles. (a) SEM image of PDA and PDAH nanoparticles, (b) FTIR spectra of heparin polymer, dopamine, PDA and PDAH nanoparticles, (c) BMP-2 entrapment efficiency of PDA and PDAH nanoparticles, (d) CCK-8 assay results of MC3T3 cocultured with different concentration of PDAH nanoparticles for 1–7 days, (e) DPPH scavenging ability of different concentration of PDA and PDAH nanoparticles, (f) EDS spectra and quantitative analysis of C, N, O and S elements of PDAH nanoparticles, (g) EDS mapping results of PDA and PDAH nanoparticles.