Fabrication of electrochemical NO sensor based on nanostructured film and its application in drug screening

As a transcellular messenger molecule, nitric oxide (NO) is involved in many physiological and pathological processes. The accurate quantitative detection of NO in vivo is particularly important. In this work, a novel electrochemical NO sensor was fabricated via electro-polymerization of ethylenediamine (EDA) on multi-walled carbon nanotubes (MWNTs) film. The sensor combined the porous structure and good conductivity of MWNTs with the good electro-catalytic ability of p-EDA film. For the detection of NO, it has a linear range from 95 nM to 11 μM and the limit of detection reaches 95 nM with excellent reproducibility. So it was successfully applied to monitor NO release from rat liver sample for investigating the inhibition or promotion effect of drugs including oleanolic acid (OA), baicalin and Nω-nitro-L-arginine methyl ester (L-NAME) on nitric oxide synthase (NOS). The results showed that OA could promote NO release and the amount of NO increases about 1.9 times, but baicalin and L-NAME could inhibit the release of NO and the amount of NO decreased by two-thirds and 37.5%, respectively.