Synthesis of dopamine-derived N-doped carbon nanotubes/Fe3O4 composites as enhanced electrochemical sensing platforms for hydrogen peroxide detection.

A novel preparation of dopamine-derived N-doped carbon nanotubes/Fe3O4 composites (N-CNTs/Fe3O4 Cs) is demonstrated via facile hydrothermal route and calcination treatment. In this approach, dopamine was selected as N-containing precursor, which can promote Fe3O4 nanocrystal deposition uniformly on the surface of CNTs and effectively modulated the graphitic structure with doped pyridinic N and graphitic N to improve the electrochemical performance of carbon composites. More interestingly, the inhibited growth of the Fe3O4 crystal during calcination can be effectively avoided by soaking PDA-CNT/Fe3O4 Cs in a phosphate solution before calcination. The N-CNTs/Fe3O4 Cs have an enhanced electrocatalytic activity toward hydrogen peroxide with high sensitivity (316.27 mA M-1 cm-2) and wide linear range (0.006-2.057 mM). The N-CNTs/Fe3O4 Cs modified sensor was successfully applied to real-time detection of H2O2 released from living cancer cells, displaying a potential application in the study of oxidative stress-related diseases. This work demonstrates a rational way for high-performance electrocatalytic material synthesis and bioanalysis. Graphical abstract An enzyme-free biosensor of H2O2 was constructed on the basis of dopamine-derived N-doped carbon nanotubes/Fe3O4 composites (N-CNTs/Fe3O4 Cs), and it exhibited the enhanced electrocatalytic activity for H2O2 detection with high sensitivity, wide linear range, and outstanding reproducibility and stability.