Figure 7.

Reduced diffusion of R6G during the early stage (within 15 h) of extrafibrillar mineralization results in a nucleation barrier in a later stage of collagen mineralization (after additional 23 h). (a) Diffusion times of R6G into MC0p and MC10p at different depths after 15 h of mineralization. The average and standard deviation were obtained from 10 measurements at each scanning position. Two different positions were scanned at the same depth. Diffusion times in unmineralized collagen matrix and simulated body fluid without Ca²⁺ are also indicated as gray regions for the comparison. (b, c) Spatial distributions of CaP within MC0p (b) and MC10p (c) systems at the late stage of the mineralization were influenced by the reduced diffusion of molecules required for the CaP mineralization from SBF solution into the deeper positions of the matrices. After an initial 15 h of mineralization, for in situ SAXS analysis, TEM images of thin sections were taken after an additional 23 h incubation in 3 × SBF. Scale bars are 5 μm.