Figure 2.

SEM images of electrospun polyurethane nanofibers containing different concentration of CaCl2 after 2 h (a) and 7 days (b) incubated in SBF solution for (1) 0, (2) 1, (3) 1.5 and (4) 2 wt%, respectively.

Nirmala et al. Nanoscale Res Lett 2011 6:2   doi:10.1007/s11671-010-9737-4