A High Catalytic\nActivity Nanozyme Based on Cobalt-Doped\nCarbon Dots for Biosensor and Anticancer Cell Effect

Abstract

Nanozyme technology as an emerging field has been successfully\napplied to chemical sensing, biomedicine, and environmental monitoring.\nIt is very significant for the advance of this field to construct\nnanozymes with high catalytic activity by a simple method and to develop\ntheir multifunctional applications. Here, a new type of cobalt-doped\ncarbon dots (Co-CDs) nanozymes was designed using vitamin B₁₂ and citric acid as the precursors. The homogeneous cobalt doping\nat carbon nuclear led the Co-CDs to show significant peroxidase-like\nactivity resembling natural metalloenzymes. Based on the high affinity\nof Co-CDs to H₂O₂ (<i>K</i>_m = 0.0598 mM), a colorimetric sensor for glucose detection was constructed\nby combining Co-CDs with glucose oxidase. On account of the high catalytic\nactivity of nanozymes and the cascade strategy, a good linear relationship\nwas obtained from 0.500 to 200 μM, with a detection limit of\n0.145 μM. The biosensor has realized the accurate detection\nof glucose in human serum samples. Moreover, Co-CDs could specifically\ncatalyze H₂O₂ in cancer cells to generate a\nvariety of reactive oxygen species, leading to the death of cancer\ncells, which has useful application potential in tumor catalytic therapy.\nIn this work, the catalytic activity of Co-CDs has been adequately\nexploited, which extends the application of carbon dots in multiple\nbiotechnologies, including biosensing, disease diagnosis, and treatment.