In Situ Imaging of Endogenous Hydrogen Peroxide Efflux from Living Cells via Bipolar Gold Nanoelectrode Array and Electrochemiluminescence Technology.

The integration of a closed bipolar electrode ( c -BPE) array and electrochemiluminescence (ECL) detection received a boost in applications in the detection of cell adhesion and disease-related biomarkers. This work proposed a gold nanorod array based c -BPE-ECL system to realize an in situ image of endogenous hydrogen peroxide (H 2 O 2 ) efflux from living cells and parallel analysis of endogenous H 2 O 2 released from multiple cells by converting electrochemical signals into optical signals. The gold nanorod array with high density was prepared by a repeating chronopotentiometry procedure with anodic aluminum oxide (AAO) membrane as a template. The c -BPE array was fabricated by assembling poly(dimethylsiloxane) (PDMS) chips on both sides of the gold nanorod array. When an appropriate driving potential is applied, H 2 O 2 generated from living cells at the sensing pole was reduced on the gold nanorod, triggering the oxidation of the ECL reagent at the reporting pole, which allowed the detection of H 2 O 2 released from living cells. Under phorbol myristate acetate (PMA) stimulation, H 2 O 2 released from living HeLa, HepG2, MCF-7, and LO2 cells was determined to be 47, 32.4, 25.7, and 6.3 μM, respectively. This indicated that the amount of H 2 O 2 released from PMA-stimulated cancer cells was significantly higher than that from the stimulated normal cells. This work presented a new approach for in situ imaging of H 2 O 2 released from living cells and could also be used to detect other electrochemically active or non-electrochemically active molecules through simple cell surface modification, which may have potential applications in cell apoptosis study and disease diagnosis.