We are working to develop a multi-channel microfluidic device to model human kidney function using HK-2 (human kidney proximal tubule) cells as a model cell type. Optimization of growth conditions and characterization of cells was achieved through the use of various methods including growth curves, measurement of epithelial electrical resistance, enzymatic assays, immunohistochemistry, and transport studies. These studies allowed for us to understand the growth of renal cells over time, formation of tight junctions between cells, modes of transport and permeability of these cells to proteins. The results of the characterization studies suggest that HK-2 cells can be used to model human proximal tubule function in pharmaceutical testing.