Electrochemiluminescence cytosensing platform based on Ru(bpy)32+@silica-Au nanocomposite as luminophore and AuPd nanoparticles as coreaction accelerator for in situ evaluation of intracellular H2O2

Abstract

An electrochemiluminescence (ECL) cytosensor was fabricated onto a microfluidic paper-based analytical device (μ-PAD) in order to detect hydrogen peroxide (H2O2) which was released from tumor cells. The ECL probe Ru(bpy)32+@silica-Au nanocomposite (Ru@SiO2-Au) was fabricated and served as ECL reagent. The ECL of Ru@SiO2-Au nanocomposite was quenched by the ferrocene (Fc). AuPd nanoparticles (AuPd NPs), which were modified on the paper working electrode (PWE), were served as the catalyst of H2O2 to produce hydroxyl radicals (•OH) for cleaving Fc-labelled DNA to achieve “signal-on”, and AuPd NPs also severed as coreaction accelerator. H2O2 was released from cells under the stimulation of phorbol myristate acetate. Fc-labelled DNA strand was cleaved via •OH. Fc molecule departed from the PWE surface, The ECL could be recovered. An ECL cytosensor on a 3D origami device was constructed. The ECL response of the Ru@SiO2-Au-Fc system was related to the number of cells. The ECL intensity was quantitatively related with the logarithm of MCF-7 cells number and H2O2 concentration, the detection limit was 30 cells mL−1. As a consequence, this work provided a really low-cost and disposable μ-PAD for sensitive detection of intracellular H2O2. What's more, this work had potential application value for studying cellular biology and pathophysiology.