Bacterial cellulose/gelatin scaffold loaded with VEGF-silk fibroin nanoparticles for improving angiogenesis in tissue regeneration

Due to its unique properties, bacterial cellulose (BC) has attracted a great deal of interest as an implant material for tissue regeneration. However, one major problem of BC is inadequate vascularization which leads to cell apoptosis due to insufficient nutrients and oxygen supply. Herein, porous BC/gelatin (BC/Gel) scaffolds loaded with vascular endothelial growth factor (VEGF) with silk fibroin nanoparticles (VEGF-NPs) were prepared. An in vitro study indicated that VEGF was sustainably released from the BC/Gel/VEGF-NPs scaffold over 28 days. Cell viability, morphology and proliferation were evaluated using Live/Dead((R)) viability/cytotoxicity assay, field emission scanning electron microscopy and CCK-8 assay by seeding the scaffolds with pig iliac endothelium cells. The presence of VEGF-NPs in the scaffold significantly improved cell proliferation and viability in vitro. Evaluation of in vivo biocompatibility and angiogenesis of the BC/Gel/VEGF-NPs scaffold was conducted using a dog skin defect model. Results indicated that the BC/Gel/VEGF-NPs scaffold significantly promoted vessel blood formation after implantation compared to the BC/Gel and BC/Gel/NPs scaffolds. It is concluded that angiogenesis could be improved through the incorporation of VEGF-NPs into the BC/Gel scaffold, which may enhance clinically desirable functions of BC-based scaffolds in terms of enhanced angiogenesis.