Figure 3.

Scanning electron microscopy images exhibiting effects of calcium carbonate microcapsules (1%, 2%, and 5% (w/v)) on microstructures and pore walls of the thermosensitive calcium carbonate microcapsule–2% and 5% (w/v) nanohydroxyapatite–10% (w/v) β-glycerophosphate–4:1 (w/w) chitosan/collagen (nHA–CaCO₃–chitosan/collagen) hydrogels. Hydrogels with (A,E,I,N) 0% CaCO₃, (B,F,J,N) 1% CaCO₃, (C,G,K,O) 2% CaCO₃, and (D,H,L,P) 5% CaCO₃. Hydrogels with (A–H) 2% nHA and (I–P) 5% nHA. The microstructures of the hydrogels are shown in (A–D,I–L) and surface features of pore walls (E–H,M–P). The small nHA particles are in nanometers, and the large spherical CaCO₃ microcapsules are in micrometers. The lengths of the magnification bars are 100 and 5 µm.