An electrochemiluminescence biosensor for dopamine based on the recognition of fullerene-derivative and the quenching of cuprous oxide nanocrystals

Abstract

In this work, L-cysteine (L-Cys) and 3-aminophenylboronic acid (APBA) consecutively reacts with fullerene (C₆₀) to obtain a new fullerene-derivative (L-Cys–C₆₀–APBA) with better biocompatibility, conductivity and hydrophilicity. L-Cys-functionalized C₆₀ can act as an excellent co-reactant to the electrochemiluminescence (ECL) of peroxydisulfate–oxygen (S₂O₈²⁻–O₂) system and greatly amplify the luminescence signal. APBA-functionalized C₆₀ has specific recognition to dopamine (DA) with diol structure. Therefore, a sensitive sensing interface for DA can be constructed based on the obtained L-Cys–C₆₀–APBA and the ECL of S₂O₈²⁻–O₂ system. Furthermore, cuprous oxide (Cu₂O) nanocrystals, prepared with a modified reductive solution chemistry route, can promote the oxygen reduction reaction commendably. Thus, Cu₂O modified on the electrode has a strong quenching effect to the ECL of S₂O₈²⁻–O₂ system. And the quenching effect is positively correlated with concentrations of DA, by which DA can be selectively and sensitively detected. The linear range is from 0.01 μM to 40 μM with a relatively low detection limit of 0.003 μM (S/N = 3).