Decellularised baby spinach leaves and their potential use in tissue engineering applications: Studying and promoting neovascularisation

Although significant progress has been made, delayed neovascularisation of tissue-engineered constructs still remains challenging for the survival of constructs post-grafting. The addition of laboratory expanded proangiogenic cells to tissue engineering scaffold systems prior to implantation is a promising approach to overcome the slow neovascularisation. The use of decellularised biological constructs is an emerging strategy for producing physiologically relevant scaffolds for use in both pre-clinical and clinical applications. Decellularised plant architectures have recently been proposed as one approach - here we seek to confirm and extend this work by preparing baby spinach leaves without damaging their intrinsic vascular architecture and to explore their efficacy once seeded with cells to promote neovascularisation in a chick bioassay of neovascularisation. Firstly, the in vitro biocompatibility of the decellularised spinach leaves and the effect of gelatin coating on cell attachment and proliferation were assessed. The decellularised leaves showed no toxicity to cells, and gelatin coating and the presence of fibroblasts enhanced the survival of human endothelial cells in the scaffolds. The proangiogenic activity of these cell populated scaffolds was then investigated in ex ovo chick chorioallantoic membrane assay where the presence of the endothelial cells significantly promoted angiogenesis over seven days. In conclusion, these results support a small but growing body of literature that suggests the use of decellularised plants as potential scaffolds to promote neovascularisation for tissue engineering constructs.