Simultaneous impedimetric and amperometric interrogation of renal cells exposed to a calculus-forming salt

The complexity of the cellular response, induced even by the simplest experimental stimulus, requires an increased number of cellular parameters to be simultaneously monitored. An all electrochemical system allowing the simultaneous and real-time monitoring of both cell adherence and superoxide release into the extracellular space was developed to address this challenge. Cell adherence (to neighboring cells and to substrate) was monitored using non-faradaic impedance spectroscopy while the superoxide release was monitored using a cytochrome c-based amperometric biosensor. The system was used to observe for the first time how these two cellular parameters are changing in real-time for renal cells exposed to calcium oxalate, a calculus-forming salt. It was discovered that calcium oxalate crystals decrease cell adherence and in the same time induce oxidative stress by an overproduction of superoxide. Subconfluent cells, without fully developed tight junctions, appear to be more vulnerable than confluent cells with tight junctions indicating the important protective role of these junctions.