3.2.1 Microcarrier Assay
Using this method, cytodex-3 microcarrier scaffolds can be coated with gelatin and suspended with ECs(Nehls and Drenckhahn, 1995). After 2-4 days’ incubation, ECs are attached to and cover the microcarriers, which are then embedded in a fibrin matrix. Consequently, it was observed and measured how endothelial cells (ECs) moved to form capillary-like structures. Plastic, glass, dextran, cellulose, collagen, microcarriers and fibrin with an appropriate diameter (typically 100–400 m) for cell attachment can be produced[59,78]. The type of ECM used to insert the microcarriers has a significant impact on endothelial cell activity. For example, hyaluronic acid promotes endothelial cell migration, but not capillary formation.(O’Brien et al., 2000) The ECM density also strongly regulates capillary formation(Ghajar et al., 2008)(Kniazeva and Putnam, 2009).The advantage of this model is that it does not have the EC detachment issue that 2D models do. This model’s 3D matrix enhances endothelial tube development by more accurately simulating the in vivo environment. This is a useful tool for studying the function of cell-cell and cell surface contacts for angiogenesis because it regulates a number of variables, including surface charge and integrin binding(Jong, 2005). However, like with 2D models, one limitation of this test is that EC migration is largely detected in a 2D horizontal X-Y plane.