Sandwich-type electrochemical aptasensor based on polydopamine-Au-metal ions as signal label and coralloid Au-conductive carbon architecture-modified electrode for the simultaneous detection of cardiac troponin I and myoglobin

The determination of cardiac troponin I (cTnI) and myoglobin (Myo) is increasingly significant considering their potential in acute myocardial infarction (AMI) diagnosis. Here, we constructed a sandwich-type electrochemical aptasensor for the simultaneous detection of cTnI and Myo. The polydopamine-Au-metal ions (PDA-Au-Pb2+/Cu2+) were synthesized and used as the labels of second aptamers (TrO6 and S232). The labels displayed different peaks at different potential sites, thus making the simultaneous detection method available. Meanwhile, the synthesized zirconium-based carbon architecture (CC) was well-conductive originating from the annealing process. After the modification of CC on the bare electrode (screen-printed carbon electrode, SPCE), the coralloid Au (CAu) was further decorated on the electrode by electro-deposition, thus forming CAu/CC/SPCE with high conductivity. Hence, the aptasensor proposed here showed admirable simultaneous quantitative analysis performance towards cTnI and Myo with wide linear ranges (1 μg/mL-0.01 pg/mL, 1 μg/mL-0.1 pg/mL) and low detection limits (3.8 fg/mL, 35 fg/mL). These results demonstrated that the aptasensor held the potential application in clinical diagnosis.