Roche Applied Science announces that its xCELLigence RTCA System allows for label-free, continuous monitoring of cell phenotypic changes using electrical impedance as readout. The interaction of cells with the electronic biosensors leads to the generation of a cell-electrode impedance response that indicates the status of the cells in terms of cell viability, cell number, cell morphology and cell attachment quality. Real-time, continuous measurement ensures the documentation of cell phenotypes in the form of time- dependent cell response profiles (TCRP).

The utility of the xCELLigence System was explored for assessing RNAi-mediated knockdown of gene function in recent study. Researchers focused on Eg5which is a kinesin involved in the mitosis pathway. The study results provide evidence that real-time cell monitoring utilizing the xCELLigence System is ideal for identifying the optimal time point for further biochemical and molecular analyses of cellular events. The study also showed that transfection of siRNA targeted to Eg5 produces a transient cell phenotype, with maximum expression at 27 hours post-transfection.

The real-time online feature of the xCELLigence System has made it possible to directly link phenotypic cellular events to the molecular and biochemical changes which occur after transfection with siRNA. Conventional analysis of the data at time points before or after 27 hours post-transfection would have missed the optimal window of opportunity for carrying out relevant gene and protein expression assays. In addition the real-time data stream of the system provides a continuous, label-free measure of cell culture quality control for transfection, simultaneously identifying potential off-target effects of the siRNA.