Ag-Ti₃C₂T_x MXene mediated H₂O₂ reduction for electrochemical biosensing of kanamycin in real samples based on split...

To resolve the conflict between multidimensional interferences derived from complex matrices and the stringent requirements for trace-level detection sensitivity, a novel electrochemical aptasensor was constructed for highly sensitive kanamycin (KANA) detection based on a split aptamer engineering strategy. Ag-Ti₃C₂T_x MXene, synthesized via in-situ reduction of silver nanoparticles onto the surface of two-dimensional MXene nanosheets, is employed for electrode decoration. This composite possesses abundant binding sites for aptamer 1 (Apt1) immobilization and exhibits outstanding catalytic performance in the reduction of H₂O₂. Signal acquisitions were performed under reductive potential conditions, endowing the sensor with superior anti-interference capability. Upon KANA addition, aptamer 2 (Apt2) can assemble into a ternary structure with the target and Apt1, leading to the displacement of cDNA and triggering a signal-down response. Under optimized conditions, the fabricated aptasensor presents a broad linear range of 1∼20000 nM with a limit of detection (LOD) of 0.12 nM, and exhibits excellent selectivity, reproducibility, and strong stability. In addition, the aptasensor demonstrates satisfactory recovery rates in real sample analysis, indicating its great potential for practical applications. The combination of Ag-Ti₃C₂T_x MXene nanocomposite and split aptamer engineering technology provides a feasible strategy for highly sensitive detections of trace-level antibiotic residues in complex food matrices.