Development of a customizable vascularization strategy using a modular microfluidic platform for fibroblast-free vascularized tissue.

In vascularized microphysiological systems, co-culture of fibroblasts and endothelial cells is commonly employed to induce capillary network formation through angiogenesis. However, when recapitulating organs such as brain or pancreas, which contain few or no fibroblasts, conventional fibroblast-dependent co-culture poses a limitation to physiological relevance. Here, we developed a modular microfluidic platform that allows reversible connection and disconnection of fibroblast and endothelial cell modules. When the modules were connected, fibroblast-induced angiogenesis of endothelial cells was promoted, and upon disconnection, a vascularized module composed solely of endothelial cells for fibroblast-free capillary network was prepared and able to be maintained for a certain period. We analyzed vascular morphogenesis under different conditions of fibroblast concentration and co-culture duration. We also confirmed that the preformed capillary network remained stable for up to 2 days after module disconnection. Furthermore, upon module reconnection after 2-day of disconnection, angiogenic activity was reactivated through the reestablished co-culture. This approach overcomes the limitations of conventional co-culture methods, enabling the application to organ-specific fibroblast-free vascularization conditions, and provides a foundation for investigating the interaction between preformed capillary networks and other tissues or organs.