Electrochemiluminescent (ECL) Aptasensor for Lysozyme Using a Graphene Quantum Dot (GQD)-Ruthenium Bipyridine-Silica Nanocomposite

Abstract

An electrochemiluminescent (ECL) aptasensor for lysozyme (Lyz) based on a graphene quantum dot (GQD)-ruthenium bipyridine (Ru(bpy)3 2+)-silica (GQDs-Ru(bpy)3 2+@SiO2) nanocomposite were prepared by encapsulating GQDs and the luminophore Ru(bpy)3 2+ in silica nanospheres (SiO2). The nanocomposite GQDs-Ru(bpy)3 2+@SiO2 with uniform size exhibited a strong and reproducible ECL response. The nanoprobe (DNA-GQDs-Ru(bpy)3 2+@SiO2) was obtained via amidation between GQDs-Ru(bpy)3 2+@SiO2 and the complementary DNA sequence. The ECL platform was constructed by hybridization between the aptamer and the complementary strand DNA. The specific recognition between aptamer and the target lysozyme maintained the nanoprobe DNA-GQDs-Ru(bpy)3 2+@SiO2 away from the electrode, which led to the decreasing ECL response. The aptasensor exhibited a linear relationship from 0.1 to 100 pg/mL with a detection limit of 1.7 × 10−11 mg/mL. This study provided a simple and sensitive analytical approach for lysozyme.