Confined electrochemiluminescence in vertically ordered silica mesochannels for the imaging of hydrogen peroxide released from single cells

Abstract

Here, the confined electrochemiluminescence (ECL) of luminol and hydrogen peroxide is achieved in vertically ordered silica mesochannels (SMCs) and applied to map the efflux of hydrogen peroxide from single living cells. The vertical alignment of SMCs on indium tin oxide (ITO) slides restricts the lateral diffusion of species generated in the ECL process. Accordingly, the cross-talk of luminescence intensity from nearby microregions is minimized for higher-spatial-resolution ECL imaging. The characterization of luminol ECL on these SMC-coated slides yields a detection range of hydrogen peroxide between 5 μM and 1 mM, providing high sensitivity in imaging the efflux of hydrogen peroxide from cells. Compared with the luminescence from individual cells on bare ITO slides, ~4-fold intensity is observed for SMC-coated ITO, suggesting a better electrode surface for single-cell ECL imaging. Keywords: Confined electrochemiluminescence, Silica mesochannels, Luminol, Hydrogen peroxide, Single-cell imaging