A Dual-Ion Synergistic Catalysis Utilizing Zn-Regulated CdSSe ECL Immunosensor Employed for the Ultrasensitive CA19-9 Detection.

Carbohydrate antigen 19-9 is a well-known malignancy biomarker, and its sensitive detection is particularly crucial in the diagnosis and assessment of pancreatic cancer. In this study, an ultrasensitive CA19-9 immunosensor was constructed using the Zn-regulated CdSSe (Zn-CdSSe) nanospheres (NSs) as the electrochemiluminescence (ECL) emitter and FeCoS nano octahedrons (NOs) as a coreactant enhancer. The microstructure of ternary transition metal chalcogenide CdSSe was precisely tuned by Zn doping to avoid aggregation and thus enable stable and efficient cathodic ECL responses. The bimetallic sulfide FeCoS was synthesized using a metal organic framework (MOF) as the template by ion permeation. It was able to catalyze the coreactant efficiently due to the synergistic effect of the Fe and Co. The immunosensor exhibited low detection limit (7.6 × 10 U mL) in the wide linear range of 0.0001-100 U mL, offering a sensitive CA19-9 detection method.