Fig. 6. (a) CCK-8 assay results of CCS–PVA, 10 wt%, and 20 wt% ACP–CCS–PVA composite membranes. The ALP activity (b) and staining (c) were on the 7th and 14th days. (d) The alizarin red staining was on the 14th and 21st days (*P < 0.05, **P < 0.01, n = 3).