Mn-Doped CeO₂ Nanorods for the Colorimetric Sensing of Glutathione

Nanozymes with high peroxide (POD)-like activity have great practical potential in the colorimetric sensing of biomolecules in the medical and biological fields. However, their applications are limited by some disadvantages such as their low catalytic activity and poor biocompatibility. While designing and synthesizing nanozymes, elemental doping is used as an effective method to improve their enzymatic activity. Herein, CeO2 nanorods doped with different concentrations of Mn were synthesized via the hydrothermal method. Mn doping effectively improved the POD-like activity of the CeO2 nanorods. Notably, MnCe0.1 exhibited superior POD-like activity to that of CeO2. The improvement in the catalytic activity of MnCe0.1 was attributed to the presence of more exposed active sites and more oxygen vacancies compared with those of CeO2 nanorods. Using its excellent POD-like activity, the developed system exhibited linear detection ranges of 10–100 μM and 2.5–20 μM and detection limits of 1.94 μM and 0.37 μM for H2O2 and glutathione detection, respectively. Additionally, the developed MnCeX nanomaterials exhibit remarkable temporal stability and reusability. Finally, considering the excellent POD-like activity of MnCe0.1 nanozymes, they have good prospects for cancer treatment.