Functionality of MDCK kidney tubular cells on flat polymer membranes for biohybrid kidney

The prerequisite for the development of a biohybrid artificial kidney, is a substrate for confluent growth of renal cells forming an epithelial monolayer without any leaks. Conventional cell culture supports cannot be adapted for this purpose, because they lack adequate mechanical properties and thermal stability. From two suitable materials, polysulfone and polyacrylonitrile, two permeable polymeric membranes have been produced that were, according to ISO 10993-5, not cytotoxic. Cloned Madin Darby Canine Kidney (MDCK) cells (an established renal cell line) were cultured on the surface of the plastic materials, and on conventional cell culture supports. With all materials, assays of mitochondrial and lactate dyhydrogenases exhibited similar proliferation and the viability of the MDCK cells. Transmission electron microscopy showed the expression of a normal morphology of kidney tubular cells. Perfect barrier function, consequent on the formation of intercellular junctions in a confluent tight epithelium, was visualized in electron micrographs, and quantified by measurement of the transepithelial resistance. The uniformity of the cells grown was demonstrated in samples by electron microscopy and in the whole epithelium by intravital impedance analysis. It was concluded that polymeric membranes produced from polysulfone or polyacrylonitrile are appropriate substrates in the design of biohybrid kidney devices.