Highly Sensitive Dual-Signal Amplification Electrochemiluminescence Aptasensor Based on Platinum Electrode Modified with Multi-Walled Carbon Nanotubes-Titanium Dioxide and Thionine for Kanamycin Detection

A dual-signal-amplified electrochemiluminescence (ECL) aptasensor based on multi-walled carbon nanotubes@titanium dioxide/thionine (MWCNTs@TiO 2 /Thi) was proposed to detect kanamycin (KAN) based on the chemiluminescence properties of luminol-hydrogen peroxide (H 2 O 2 ) in alkaline solution. The MWCNTs@TiO 2 with large specific surface area and advantageous biocompatibility could accelerate electron transfer and enable high loading of luminol to enhance ECL intensity. Thi, as a perfect electronic mediator, it can also accelerate electron conductivity to further enhance ECL intensity. With the high charge transfer property of MWCNTs@TiO 2 and Thi, the ECL intensity of the aptasensor was obviously promoted. When the target KAN existed, ECL signal decreased significantly due to the specific interaction between KAN and the aptamer. Therefore, KAN concentration could be determined according to the intensity of ECL. Under the optimal conditions, the developed aptasensor showed a wide linear range from 1×10 -3 to 1×10 5 ng mL -1 with a low detection limit of 0.073 ng mL -1 (S/N = 3). The aptasensor showed high specificity, good reproducibility and long-term stability. Simultaneously, the application of the proposed ECL aptasensor will open an efficient approach for highly sensitive detection of KAN in food safety.