FIG. 2.

Gelatin microspheres (<100 μm in diameter) dispersed in the hydrogel were stained blue (A) and were visible in SEM images (C) before dissolution. After a 2-day incubation at 37°C, most of the gelatin microspheres dissolved and diffused out from the hydrogel (B), resulting in a porous structure (D). SEM, scanning electron microscopy.