In Vitro Development of Microvessels Using a Scaffold of Cylindrical PLGA

The microvascular network is a simple but critical system that is responsible for various important biological mechanisms in the bodies of all animals. The ability to generate a functional microvessel in vitro not only makes it possible to engineer vital tissue of considerable size but also serves as a platform for biomedical studies. In this study, we propose a simple method for fabricating customized cylinder micro-scaffolds for the in vitro development of microvascular networks. By integrating micro-electro-mechanical systems techniques with thermal reflow, we design and fabricate a micro-scale hemi-cylinder photoresist template. Then, a replica mold of polydimethylsiloxane, produced by casting, is used to generate microvascular network scaffolds of poly(lactide-co-glycolide) (PLGA). We selected the human umbilical vein endothelial cell (HUVEC) as our model endothelial cell, seeded it onto both sides of the PLGA scaffold, and cultured it using a traditional approach with no pumping system. Results from fluorescent staining demonstrate that the scaffold was covered with HUVECs and that the desired microvascular network and pattern was generated in vitro. The proposed method enables the culture of cells on a scaffold using a conventional culture approach and allows continuous monitoring of cell conditions. The cell-covered scaffold can serve as a framework for building large tissues, while the formed microvascular network, after degradation of the biodegradable PLGA cylinder, can be used as the core of a vascular chip for in vitro circulation studies.