Fig. 4

Characterization of ZIF-8/PCL composite after biomimetic mineralization. Flake-like PCL and ZIF-8/PCL prepared within the cylindrical mould. a) SEM images showed that crystals substantially deposited onto flake-like ZIF-8/PCL surface following SBF incubation under high and low magnifications. b) According to ZIF-8/PCL elemental mapping, crystal deposits included Ca, Zn and P elements. c) 3D micro-CT images for flake-like ZIF-8/PCL reconstruction revealed that bone-like apatite crystals deposited increasingly as time went by. d) Quantification on the ratio of apatite volume to total volume acquired based on stereograms. e) Young’s modulus of PCL was compared with ZIF-8/PCL, which revealed no obvious heterogeneity, and PCL was likely to become flexible following blending using ZIF-8. f) Static water contact angle was measured, as a result, adding ZIF-8 enhanced PCL surface roughness, especially following 7-day mineralization. g) AFM images revealed alterations of roughness following 24-h mineralization at the nanoscale. *** p < 0.001, ns: not significant. (n = 4)