Microfluidic model is developed for investigating 3D in vitro biological phenomenon such as human breast cancer cell metastasis and antimicrobial activities. The metastasis model employs vasculogenesis driven microvascular network, which is generated with mural cells, and either osteo-differentiated or myoblast cells, in addition to human umbilical endothelial cells to mimic the organ-specific microenvironments. The developed microvasculature is thus used to model organ-specific cancer cell extravasation into bone- and muscle-mimicking microenvironments. Cytokines are identified for their roles resulting in increased or decreased extravasation for each conditions. Furthermore, developed microfluidic system allows the maintenance of linear antibiotic concentration and
measurement of local bacterial density to show their effectiveness in treating Pseudomonas Aeruginosa. Therefore, the microfluidic models can mimic metastatic properties as well as infection of the microenvironments, and potentially give the insights on the different properties of organotypic microenvironments.