1. Temporal and Sequential Delivery of Multiple Growth Factors Affects Vascularization Inside 3D Hydrogels
--> Here, combinations of angiopoietin-1, angiopoietin-2, and PDGF-BB improve vascularization of a human umbilical vein endothelial cells-fibroblast coculture inside polyethylene glycol-based hydrogels the most, while the optimal concentrations and time points of growth factor addition are determined. Moreover, fibroblasts, pericytes, and mesenchymal stem cells (MSCs) are compared as supporting cells, of which MSCs best promote vascularization in coculture. Additionally, the resulting blood vessels align with magnetically oriented rod-shaped microgels when cultured inside the Anisogel. To mimic fibrosis, transforming growth factor-beta is added, resulting in significantly smaller vessels and more collagen secretion. This in vitro study reveals that a cascade of growth factors can improve vascular formation in 3D hydrogels, which is important to create viable tissue-engineered constructs for therapies and in vitro healthy and diseased tissue models.
2. Cell-interlinked macroporous annealed particle scaffolds for tissue engineering (Cellular Architects at Work: Cells Building their Own Microgel Houses)
--> In this work, a cell-induced interlinking method for MAP scaffold formation is established, which avoids the necessity of chemical crosslinkers and pre-engineered pores to achieve micro- or macropores in these 3D frameworks. This method enables cells to self-organize with microgels into dynamic tissue constructs, which can be further controlled by altering the microgel properties, the cell/microgel ratio, and well shape. To form a cell-induced interlinked scaffold, the cells are mixed with dextran-based microgels and function as a glue between the microgels, resulting in a more homogenous cell distribution throughout the scaffold with efficient cell–cell interactions.
