A rapid colorimetric method for determining glutathione based on the reaction between cobalt oxyhydroxide nanosheets and 3,3′,5,5′-Tetramethylbenzidine

As an antioxidant, glutathione (GSH) can react with reactive oxygen species (ROS) and heavy metals to help alleviate oxidative stress (OS) and damage in cells. Accurately measuring the GSH level is important to gauge the integrity of cell redox buffering capacity. In this work, a convenient method for qualitative and quantitative determination of GSH was developed based on the reaction between CoOOH nanosheets and 3,3′,5,5′-tetramethylbenzidine (TMB). Colorless TMB solution can be oxidized by CoOOH to oxidized TMB (oxTMB) which is blue in color. However, in the presence of GSH, CoOOH preferentially reacted with GSH, producing less oxTMB and lighting the blue color. The changes of the blue color of oxTMB can be directly observed by naked eyes and accurately measured by UV–vis absorbance at 652 nm. Based on that, GSH can be detected in a wide range from 0.1 to 300 µM with a low limit of detection of 0.08 μM which was performed with a quantitative high-throughput 96-well plate. In addition, GSH in human SH-SY5Y neuroblastoma cells was successfully determined using our method, and the results show excellent agreement with those measured by a commercial GSH detection kit based on the use of Ellman’s reagent.