Enzyme activity-enhanced MIL101(Fe) loaded PdSn Nanoenzymes enable ultrasensitive detection of oxytetracycline in foods.

The growing problem of antibiotic abuse has become a major peril to human health. Therefore, it is crucial to develop an accurate, extremely sensitive, and efficient detection method. This study synthesized PdSn alloys with enhanced peroxidase activity via p-d orbital hybridization and immobilized them on MIL101(Fe), fabricating a novel nanoenzyme (PdSn/MIL101(Fe)). Benefiting from synergistic interactions, the nanozyme exhibits enhanced electrical conductivity and remarkable peroxidase-like activity, enabling efficient electron transfer. We constructed an electrochemical aptasensor by combining PdSn/MIL101(Fe) with signal probes (SP) as a tracer label and achieved the detection of oxytetracycline (OTC) using cyclic voltammetry (CV) and amperometric measurement. The aptasensor had a broad linear range (100 fg mL-1 to 100 ng mL-1) and a low limit of detection (LOD) of 8.13 fg mL-1. These superior characteristics endowed the aptasensor with excellent capability for OTC detection in both real samples and quality control samples.