Figure 4.

Phenotype of monocyte cells encapsulated in the 5% GelMA system as an in vitro model for brain immune response after different drug delivery profiles were delivered through the dual-layered microchannel chip system. A) Compressive modulus of monocytes encapsulated in 5% GelMA hydrogel with various UV time (* P < 0.05). B) and C) Fluorescent images of monocytes stained using calcein (green) for live cells and ethidium homodimer-1 (red) for dead cells at day 0 (B) and day 7 (C). D) Schematic of experimental set-up showing monocytes encapsulated in GelMA hydrogel on top of the dual-layered microchannel chip. E) – I) Immunostaining of CD206 (green) as an M2 macrophage, nuclei (blue), and 27E10 (red) as an M1 macrophage for samples with: E) no infusions (negative control); F) an initial DEX infusion and repeated DEX infusions; G) an initial IL-4 infusion only; H) an initial DEX infusion and repeated IL-4 infusions; I) an initial IL-4 infusion and repeated IL-4 infusions at week 1. J) Ratio of M2:M1 differentiated macrophages for all delivery profiles at 1 and 2 weeks indicating that repeated infusion of IL-4 significantly increases the presence of anti-inflammatory M2 macrophages (* P < 0.05).