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.