Fe₃O₄/Carbon Nanodot Hybrid Nanoparticles for the Indirect Colorimetric Detection of Glutathione

In recent years, carbon nanodots (CNDs)-based hybrid nanomaterials with enzyme-like properties have received considerable attention because of the simplicity of their preparation, storage, and separation, as well as cost-effectiveness compared with natural enzymes. Here, Fe3O4/CNDs hybrid nanoparticles (NPs) are prepared via a hydrothermal method, and they possess excellent peroxidase-like catalytic activity. During the synthesis, the formation and surface state of Fe3O4 NPs were extremely affected by solutions of CNDs, which served as solvents. Fe3O4/CNDs hybrid NPs with abundant hydroxyl and carboxyl groups exhibit better catalytic kinetics than natural horseradish peroxidase (HRP) to produce a rapid chromogenic reaction. Such characteristics from Fe3O4/CNDs hybrid NPs led us to develop a colorimetric method for rapid and selective determination of glutathione with the detection limit of 0.058 μM. Our approach offers a simple and novel method to prepare Fe3O4/CNDs hybrid NPs with modified CNDs, and their applications may be extended to biosensors, medical diagnostics, and environmental monitoring.