Fig. 4.

A microfluidic model for simulating the biochemical microenvironment of urinary system. (A) The distinctive microenvironments of tumors. The multiple stromal cell types create a succession of tumor microenvironments that change as tumors invade normal tissue and thereafter seed and colonize distant tissues. The abundance, histologic organization, and phenotypic characteristics of the stromal cell types, as well as of the ECM (hatched background), evolve during progression, thereby enabling primary, invasive, and then metastatic growth [68]. Reproduced with permission [68]. Copyright 2011, Cell Press. (B) Kidney-on-a-chip is developed for monitoring nephrotoxicity. Schematic design and actual image of a kidney-on-a-chip. Junctional protein expression of each group. The static and shear groups are measured before exposure to gentamicin. All groups show improved polarization compared to Transwell cultures [112]. Reproduced with permission [112]. Copyright 2016, IOP Publishing Ltd.