Fig. 2.

Characterization of osteogenic VDGH microgels. A) Gross view, low-power (i) and high-power (ii) SEM images of DBM. B) Photograph of VDGH microgels indicating DBM powders dispersed inside the microgels (i). SEM images and surface views of VDGH microgels (ii). Red arrows represent DBM. C) Young's modulus of the microgels tested by AFM. The Young's moduli of VDGH (DBM region) were significantly higher than those of other microgels (GelMA and GelMA/HAMA), and VDGH (Gel region). D) The cumulative release of VEGF in VG and VDGH microgels. E) The remaining mass ratio in PBS and different enzyme solutions showing the in vitro degradation of VDGH microgels. F) In vivo degradation evaluation of VDGH microgels in the subcutaneous environment of nude mice. VG: VEGF-loaded GelMA; VDGH: VEGF/DBM-loaded GelMA/HAMA. Statistical significance: ***p < 0.001. (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)