The Chemiluminescence Sensing Of Aminothiols In Biological Fluids Based On Functionalized Gold Nanoparticles

Aminothiols including cysteine (Cys) homocysteine (Hcy),glutathione (GSH), cysteinylglycine (Cys-Gly) and glutamylcysteine(Glu-Cys), are of importance for clinical diagnostics of a variety ofmetabolic disorders and human diseases. They have the similar chemicalproperties, because they all have the active group of–SH. Therefore, theaccurate and simultaneous measurement of these aminothiols inbiologicalfuids is desirable for research purposes and routine clinical usebecause of extensive interconversion of aminothiols. However,aminothiols require derivatization before detection. On the other hand, thedynamic range of the traditional methods is quite narrow with a highdetection limit, and cannot be used in practical use. Therefore, weinvestigated the chemiliminescence sensing of aminothiols based on thefunctionalized gold nanoparticles. The main content of research is asfollow: (1) Gold nanorods were firstly found to exhibit a tremendouslyhigher catalytic activity towards luminol chemiluminescence thanspherical gold nanoparticles. More importantly, ultra-trace aminothiolscan cause a great CL decrease in the gold nanorod-catalyzed luminolsystem by the formation of Au-S covalent bonds on the ends of goldnanorods. The system has been used to determine the glutathione in thecell extracts of Saccharomyces cerevisiae.(2) A novel method was used to synthesize triangular goldnanoparticles quickly and easily. The as-prepared triangular AuNPsowned higher surface-to-volume ratio and more active surface sitescompared to spherical AuNPs. It was firstly found that triangular AuNPsdisplayed greater catalytic activity towards luminol chemiluminescence.More interestingly, ultra-trace aminothiols can form Au-S covalent bondson the surface of triangular AuNPs, resulting in a great decrease in CLintensity. We have investigated the enhancement mechanism of triangularAuNPs and the inhibition mechanism of aminothiols.(3) We utilize the as-prepared triangular AuNPs as novelpostcolumn CL reagents to explore a simple high performance liquidchromatography-CL method for the determination of five aminothiols.The detection limits for the aminothiols were about0.1pmol. Thismethod has been used in the determination of aminothiols in human urineand plasma samples with satisfactory results.