Detection of nitric oxide in macrophage cells for the assessment of the cytotoxicity of gold nanoparticles

In this paper, an electrochemical method using a nitric oxide sensor was employed for quantitative evaluation of NO released from AuNPs-treated macrophage cells. Our results indicate that the AuNPs initiate NO release from macrophage cells and the amount of NO released is positively correlated with concentration of AuNPs. Meanwhile, total nitrite/nitrate concentrations in the AuNPs-treated macrophage cells have been determined via the Griess reaction and we demonstrate that the variation of the nitrite/nitrate concentrations is in accordance with that measured by the electrochemical method. In contrast to the citrate-coated gold nanoparticles (CT-AuNPs), when AuNPs were protected by thiolated poly ethylene glycol (PEG), the NO-releasing in macrophage upon the addition of AuNPs was relieved, implying that the PEG-coated AuNPs having less cytotoxicity and oxidative stress potential is probably due to inhibition of NO production. In conclusion, this work has demonstrated an effective sensing platform for the evaluation of the cytotoxicity of AuNPs by detecting the extracellular NO released from macrophage cells.