In vitro monitoring of i-NOS concentrations with an immunosensor: The inhibitory effect of endocrine disruptors on i-NOS release

► We examined cytotoxic effect of endocrine disruptors (EDs). ► In vitro inducible nitric oxide synthase (i-NOS) concentration was monitored. ► i-NOS immunosensor was applied to monitor in vitro i-NOS concentrations. ► Bisphenol A in all EDs was most effective to i-NOS release. The amperometric immunosensor has demonstrated the toxicity of endocrine disrupters (EDs) through monitoring the in vitro i-NOS concentration change, where the antibody of inducible nitric oxide synthase (i-NOS) was immobilized on the conducting polymer–gold nanoparticles composite. The performance of the sensor and the experimental parameters affecting the immunoreaction were optimized. Neuronal cells treated by EDs decreased in the in vitro i-NOS concentration. The effect of bisphenol A (BPA) on the i-NOS concentration released in the cells was investigated with different incubation times, and the interfering by nonspecific binding species present in a neuronal cell lysate was also examined. Of all the tested EDs, BPA showed the inhibitoriest effect and the minimum inhibitory concentration of BPA affecting the i-NOS concentration was 0.09 ± 0.005 μM. The result shows that monitoring of i-NOS in the neuronal cells treated by EDs will be a useful method to evaluate the toxic behavior of EDs.