Vascularization is important in almost all tissues, especially in dense 3D bioprinted structures. For this, we are currently in the early stages of developing a bioink specially made for vascularization. In the pipeline is to develop a whole system for dynamic cell culture. Right now we are co-culturing our vascular bioink in a static culture for evaluation.
The aim of the project is to evaluate and optimize an angiogenesis promoting bioink.
One of the fundamental difficulties that the rapidly evolving field of bioprinting is facing is supplying oxygen and nutrients to, and draining waste products from, the cells embedded in a bioink. Up till now, the common practice has been to submerge printed tissues with either relatively low cell densities or thin geometries, in cell culture media, allowing all nutrient and waste exchange to occur through simple diffusion. However, naturally dense tissues of substantial thickness require the establishment of a microvascular network.
The vascular bioink should provide a 3D environment for cellular processes that we associate with the establishment of vascular networks. Such a bioink should allow live cell imaging of endothelial cells during formation and connection of sprouts, hollow tube formation and remodelling of the vascular network into a branched and functionally perfused vascular bed.
Human umbilical vein endothelial cells and dermal fibroblasts were expanded using standard cell culture methods prior to embedding in a bioink. Once printed, the bioink was crosslinked and the constructs were cultured for 14 day in a static culture.
At the edge of the bioprint, the vascular sprouts are readily growing which can be seen at the image beside.
Initial testing provided strong evidence that extensive endothelial sprout formation did occur in the evaluated bioink.