Au Nanoparticles on Polydopamine Nanotubes for Enzyme-Like Nanomaterials with Improved Activities

The strong interaction between the polydopamine (PDA) surface and metallic ions has offered numerous opportunities to design various functional nanomaterials. Herein, we reported the in situ growth of Au nanoparticles (AuNPs) on PDA nanotubes (PDANTs) to form PDANTs@AuNPs and study the enzyme-like activities with carbonized PDANTs@AuNPs (C-PDANTs@AuNPs). The peroxidase-like and oxidase-like activities of C-PDANTs@AuNPs were significantly enhanced by the synergistic effects between C-PDANTs and AuNPs. Such effects on the oxidase-like activity of C-PDANTs@AuNPs were further revealed in electrochemistry studies. With the combination of highly conductive AuNPs, C-PDANTs@AuNPs can mimic the efficient oxidase-like catalysis of O2 to O2•–. Besides, the potential application of C-PDANTs@AuNPs was explored in the sensitive detection of glutathione using their oxidase-like activity. A calibration curve was established over a concentration range from 0.040 to 15 μM with a detection limit of 0.032 μM. The present study may open avenues for the preparation of new enzyme-like nanomaterials based on the PDA surface chemistry.