Fig. 5.

A microfluidic model for simulating the physical microenvironment of urinary system. (A) Glomerulus-on-a-chip microfluidic: podocytes and endothelial cells are cultured on opposite sides of an artificial membrane. Endothelial cells are also affected by blood flow shear force. This chip device can recreate capillary pressure by supplying perfusion flow in the upper microchannel and introducing mechanical forces [137]. Reproduced with permission [137]. Copyright 2022, Springer Nature. (B) A pathological glomerular microenvironment was established by perfusion flow regulating mechanical forces [81]. Reproduced under terms of the CC-BY license [81]. Copyright 2016, Springer Nature. (C) Modelling the human glomerular capillary wall with an organ-on-a-chip microfluidic device. Arrow shows directional flow of molecules from the capillary lumen to urinary space. Cyclic mechanical strain was applied to cell layers by stretching the flexible PDMS membrane using vacuum [82]. Reproduced with permission [82]. Copyright 2017, Springer Nature. (D) Human Bladder-chip model of UTI recapitulates the physiology of bladder filling and voiding. Human bladder epithelial cell line (epithelium, top) and primary human bladder microvascular endothelial cells (endothelial, bottom) on either side of the stretchable and porous membrane. Pooled human urine diluted in PBS and endothelial cell medium were perfused in the apical and vascular channels respectively to mimic bladder physiology. A negative pressure in the ‘vacuum’ channels (magenta) on either side of the main channel was applied to stretch the porous membrane to mimic stretching of the bladder [83]. Reproduced under terms of the CC-BY license [83]. Copyright 2021, eLife Sciences Publications.