Gold nanoparticles-based catalysis for detection of S-nitrosothiols in blood serum

Accumulating evidence suggests that S-nitrosothiols (RSNOs) play key roles in human health and disease. To clarify their physiological functions and roles in diseases, it is necessary to promote some new techniques for quantifying RSNOs in blood and other biological fluids. Here, a new method using gold nanoparticle catalysts has been introduced for quantitative evaluation of RSNOs in blood serum. The assay involves degrading RSNOs using gold nanoparticles and detecting nitric oxide (NO) released with NO-selective electrodes. The approach displays very high sensitivity for RSNOs with a low detection limit in the picomolar concentration range (5.08 × 10−11 mol L−1, S/N = 3) and is free from interference of some endogenous substances such as NO2− and NO3− co-existing in blood serum. A linear function of concentration in the range of (5.0–1000.0) × 10−9 mol L−1 has been observed with a correlation coefficient of 0.9976. The level of RSNOs in blood serum was successfully determined using the described method above. In addition, a dose-dependent effect of gold nanoparticles on the sensitivity for RSNOs detection is revealed, and thereby the approach is potentially useful to evaluate RSNOs levels in various biological fluids via varying gold nanoparticles concentration.