A novel self-enhanced ECL-RET aptasensor based on the bimetallic MOFs with homogeneous catalytic sites for kanamycin detection

The inappropriate use of antibiotics undoubtedly poses a potential threat to public health, creating an increasing need to develop highly sensitive tests. In this study, we designed a new type of porphyrin metal-organic frameworks (Fe TCPP(Zn) MOFs) with homogeneous catalytic sites. The ferric-based metal ligands of Fe TCPP(Zn) MOFs acted as co-reaction accelerators, which effectively improved the conversion efficiency of H2O2 on the surface of MOFs, then increased the concentration of •OH surrounding porphyrin molecules to achieve self-enhanced electrochemiluminescence (ECL). Based on this, an aptasensor for the specific detection of kanamycin (KAN) in food and environmental water samples was constructed in combination with resonance energy transform (RET), in which Fe TCPP(Zn) MOFs were used as luminescence donor and AuNPs were used as acceptor. Under the best conditions, there was a good linear relationship between the ECL intensity and the logarithm of KAN concentration with a detection limit of 0.28 fM in the range of 1.0 × 10−7–1.0 × 10−13 M, demonstrating satisfactory selectivity and stability. At the same time, the complexity of the detection environment was reduced, which further realized the reliable analysis of KAN in milk, honey and pond water. Overall, this innovative self-enhanced ECL strategy provides a novel approach for constructing efficient ECL systems in MOFs, and also extends the application of MOFs to the analysis and detection of trace antibiotics in food and the environment.