Engineering Microvascular Networks in LED Light-Cured Cell-Laden Hydrogels

The success of tissue engineering inevitably depends on the fabrication of tissue constructs that can be vascularized and that anastomose with the host vasculature. In this report we studied the effects of light-emitting diode (LED) photopolymerized gelatin methacryloyl hydrogels (GelMA), encapsulated with stem cells from the apical papilla (SCAP) and human umbilical vein endothelial cells (HUVECs), in promoting vasculature network formation as a function of hydrogel physical and mechanical properties, as well as total cell density. Lithium acylphosphinate (LAP) was used as the photoinitiator in concentrations of 0.05, 0.075, 0.1% (w/v). GelMA hydrogel precursors of 5% (w/v) were encapsulated with co-cultures of SCAPs and HUVECs at different cell densities (1x, 5x and 10x106 cells/ml) and photocrosslinked for 5 s. Results suggested that the compressive modulus of GelMA hydrogels increased as a function of LAP concentration, and had a maximum stiffness of 3.2 kPa. GelMA hydrogels photopolymerized using 0.0...