An ultrasensitive electrochemiluminescence biosensor for the detection of concanavalin A based on Au nanoparticles-thiosemicarbazide functionalized PtNi nanocubes as signal enhancer

A sandwich-configuration electrochemiluminescence (ECL) biosensor was constructed for detecting concanavalin A (ConA) based on peroxydisulfate/oxygen (S2O82−/O2) system. In this work, the gold nanoflower modified Zn-doped SnO2 was used as a substrate to adsorb recognition element horseradish peroxidase (HRP) for binding ConA. Then, Au nanoparticles-thiosemicarbazide functionalized PtNi nanocubes (AuNPs-TSC-PtNi NCs), as a novel ECL signal tracer, were incubated onto the electrode through a specific carbohydrate-ConA interaction, thus achieving a sandwiched structure. The integration of amplifying effect of both TSC and PtNi NCs on the ECL of S2O82−/O2 system endowed the biosensor a high sensitivity. The linear range for ConA detection was from 0.0010 ng/mL to 10 ng/mL with a detection limit of 0.0002 ng/mL (S/N=3).