Enhanced Iridium Complex Electrochemiluminescence Cytosensing and Dynamic Evaluation of Cell‐Surface Carbohydrate Expression

A newly prepared [(ppy)2 Ir(dcbpy)](+) ⋅PF6 (-) (ppy: 2-phenylpyridyl; dcbpy: 4,4'-dicarboxy-2,2'-bipyridyl) and gold nanoparticle functionalized mesoporous silica nanoparticle (Au/Ir-MSN) is reported. Based on the binding between concanavalin A (Con A) and mannose, the novel nanoparticle was applied to an ultrasensitive electrochemiluminescence (ECL) in situ cytosensing strategy and the dynamic evaluation of cell-surface carbohydrate expression. The ECL activity of the presented Con A@Au/Ir-MSN nanoprobe was greatly enhanced by employing a functionalized nanoparticle and graphene nanomaterial with an increased surface area and simultaneously improved electron-transfer efficiency at the electrode interface. Under optimal conditions, the sandwich-type ECL cytosensor showed a linear response to K562 cells at concentrations ranging from 1.0×10(2) to 1.0×10(6) cells mL(-1) and realized a low detection limit of a single cell. The proposed method could also be successfully used for monitoring the dynamic variation of carbohydrate expression in cancer cells in response to external stimulation by an inhibitor.