Magnetic graphene oxide-based electrochemiluminescent aptasensor for thrombin

A new electrochemiluminescence (ECL) reagent, iridium(III) complex (Ir(III) complex), has been synthesized and applied to develop an ECL biosensor for thrombin. The Ir(III) complex has been conjugated to aptamers firstly and adsorbed on magneto-controlled magnetic graphene oxide. In the presence of the target (thrombin), the aptamers will release into solution and result in increased ECL intensity. The enhanced ECL intensity has a direct relationship with the logarithm of thrombin concentration in the range of 2.0 × 10−9 to 5.0 × 10−8 mol/L. The detection limit was 1.3 × 10−9 mol/L (S/N = 3). The proposed method has good stability and reproducibility.