Cell-laden gelatin methacryloyl fibres fabricated using bessel beams for controlled endothelial cord formation

Abstract

In order to engineer viable three-dimensional (3D) tissue, vascular networks need to be incorporated into the tissue to prevent cell necrosis caused by insufficient access to nutrients. In this project, we propose a method to produce viable vascular endothelial cords in vitro. Human Umbilical Vein Endothelial Cells (HUVECs) were encapsulated within Gelatin Methacryloyl (Gelma) hydrogel fibres by exposing a pre-polymer cell-loaded solution to a UV laser Bessel Beam, which possesses several unique properties, such as self-healing and non-diffractive properties, that enable the polymerization of a free-standing cell-laden Gelma fibre from a single exposure. By manipulating the optical setup and laser power, Gelma fibre diameters fabricated experimentally could be tuned based on mathematical models. After exposure to UV, cell viability was high (>95%) and cells proliferated with time. Under confocal microscopy, encapsulated HUVECs were observed to self-assemble into endothelial cords with circular actin cross-sections. Compared to other techniques, the free-standing nature of the fabricated cords offers several advantages including the ability to be harvested and co-cultured with parenchymal cells. The fabricated cords could potentially find applications in regenerative medicine as well as in vitro models to study vascular physiology.