Electrofluorochromic imaging analysis of dopamine release from living PC12 cells with bipolar nanoelectrodes array

The coupling of bipolar electrode (BPE) arrays and electrofluorochromic (EFC) imaging has exhibited great abilities in bioanalysis. However, the imaging resolution and analytical performance are hampered by the large size of the electrode and the rapid diffusion of EFC molecules on the electrode surface. Here, to address the challenges, bipolar nanoelectrodes (BPnE) array and in situ immobilization strategy of EFC molecules were proposed. Anodized aluminum oxide (AAO) template-assisted Au nanoelectrodes array with high density was fabricated as BPnE array for high spatial imaging resolution. By electrically poly-merizing EFC molecules on the surface of single Au nanoelectrode, the rapid diffusion of EFC molecules on the electrode surface was not only avoided, but also realizing electrofluorescent imaging on an in-dividual nanoelectrode. Using dopamine (DA) released from living PC12 cells as a model, the proposed strategy exhibited an ultra-high sensitivity for DA analysis with a detection limit of 0.45 nmol/L and the DA release amount from a single cell was calculated to be 0.13 pmol/L. Moreover, the dynamic change of DA release under the drug stimulation from living PC12 cells could also be monitored.(c) 2022 Published by Elsevier B.V. on behalf of Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences.

Automated summary

The coupling of bipolar electrode (BPE) arrays and electrofluorochromic (EFC) imaging has demonstrated excellent capabilities in bioanalysis. However, the large size of the electrode and rapid diffusion of EFC molecules on the electrode surface have hindered imaging resolution and analytical performance. To overcome these challenges, bipolar nanoelectrodes (BPnE) array and in situ immobilization strategy of EFC molecules were proposed. The strategy achieved high spatial imaging resolution using anodized aluminum oxide (AAO) template-assisted Au nanoelectrodes array and avoided rapid diffusion of EFC molecules on the electrode surface by electrically polymerizing them on a single Au nanoelectrode. The proposed strategy exhibited ultra-high sensitivity for dopamine (DA) analysis and enabled monitoring of dynamic changes in DA release from living PC12 cells under drug stimulation.