Ascorbic acid-functionalized Ag NPs as a probe for colorimetric sensing of glutathione

In this work, we report the use of ascorbic acid-capped silver nanoparticles (AA-Ag NPs) as a probe for selective colorimetric detection of glutathione (GSH) in aqueous solution. This detection system was based on the GSH-induced aggregation of AA-Ag NPs, resulting in drastic changes in the absorption spectra and color of the AA-Ag NPs system. The GSH-induced AA-Ag NPs aggregation was confirmed by UV-visible spectrometry, dynamic light scattering (DLS) and transmission electron microscopic (TEM) techniques. Under optimal conditions, this method exhibited good linearity over the concentration ranges from 5.0 to 50 mu M, with the limit of detection 2.4 x 10(-7) M. This method was successfully applied to detect GSH in the presence of other biomolecules, which confirms that this probe can be used for the detection of GSH in real samples.