Supplementary Figure 2.

High resolution SEM images of (A,B) HAc-Alg hydrogel scaffolds ; (C,D) HAc-Alg/ 10wt% CaP composite hydrogel scaffolds; (E,F) HAc-Alg/ 30wt% CaP composite hydrogel scaffolds. The average particle size of hydrogels was determined by analysing the SEM images. The average particle size of calcium carbonate for HAc-Alg was too small to be measured using the SEM image at x 50,000 magnification. For HAc-Alg/10wt% CaP, the average particle size is ~60 nm. In case of HAc-Alg/30wt% CaP, the average particle size was determined using both SEM and TEM images, resulting particle size is ~60 nm in diameter. Based on the particle size analysis, the increased CaP content is likely attributed to the increased number of CaP particles instead of the crystal growth of nanoparticles.