Angiogenic property of silk fibroin scaffolds with adipose-derived stem cells on chick chorioallantoic membrane

Angiogenesis is a crucial step in tissue regeneration and repair. Biomaterials that allow or promote angiogenesis are thus beneficial. In this study, angiogenic properties of salt-leached silk fibroin (SF) scaffolds seeded with human adipose stem cells (hADSCs) were studied using chick chorioallantoic membrane (CAM) as a model. The hADSC-seeded SF scaffolds (SF-hADSC) with the porosity of 77.34 ± 6.96% and the pore diameter of 513.95 ± 4.99 µm were implanted on the CAM of chick embryos that were on an embryonic day 8 (E8) of development. The SF-hADSC scaffolds induced a spoke-wheel pattern of capillary network indicative of angiogenesis, which was evident since E11. Moreover, the ingrowth of blood vessels into the scaffolds was seen in histological sections. The unseeded scaffolds induced the same extent of angiogenesis later on E14. By contrast, the control group could not induce the same extent of angiogenesis. In vitro cytotoxicity tests and in vivo angioirritative study reaffirmed the biocompatibility of the scaffolds. This work highlighted that the biocompatible SF-hADSC scaffolds accelerate angiogenesis, and hence they can be a promising biomaterial for the regeneration of tissues that require angiogenesis.