Manganese coordination polymer nanoparticles with excellent oxidase-like activity for the rapidly and selectively colorimetric detection of glutathione

Novel kinds of manganese coordination polymer nanoparticles (Mn-IMZs CPNs) were fabricated through self-assemble of imidazole with Mn2+ ions in aqueous solution. The prepared Mn-IMZs CPNs, with remarkable stability, exhibit excellent oxidase-like activity that can effectively catalyze the conversion of the dissolved O2 to O2•−, turning the colorless 3,3′,5,5′-tetramethylbenzidine (TMB) to blue oxidized TMB (ox-TMB). Based on the inhibitory effect of glutathione (GSH) on the TMB oxidation, a rapid and highly sensitive colorimetric method for the detection of GSH was developed, and the linear ranges are 1.25–50 μM and 50–112.5 μM. Besides, the discriminative detection of GSH from cysteine was achieved by using the time lag between N-ethylmaleimide on the destruction of thiol compounds. Finally, the developed method was successfully applied in the quantification of GSH in tablets and rabbit plasma with high accuracy and good recovery.