Construction and use of an electrochemical NO sensor in a cell-based assessing system

We have constructed a cell-based assessing system for chemicals using a probe-type electrochemical nitric oxide (NO) sensor. This system can be used to assess the effects of chemicals on the nitric oxide signaling pathway in immune systems. NO was used as an indicator of a cellular immune response due to chemical exposure. RAW264.7 cells, a macrophage-like cell line, were used as a model immune cell. The novel probe-type electrochemical NO sensor, consisting of a Pt counter electrode, an Ag/AgCl reference electrode, and a gold electrode coated with a polyion complex layer, was constructed for this study. The NO sensor probe measures NO without the drawback of electrochemical interference. The detection limit of the sensor was 8.4 nM NO. The cell-based system was able to assess the immuno-activating effects of lipopolysaccharide and interferon-γ, and the inhibiting effects of l-NMMA in a dose-dependent manner.