A novel ECL biosensor for the detection of concanavalin A based on glucose functionalized NiCo₂S₄ nanoparticles-grown...

An electrochemiluminescence (ECL) biosensor was developed for detection of Concanavalin A (Con A). Chitosan/Ru(bpy)₃²⁺/silica/Fe₃O₄ nanomaterials (CRuSi-Fe₃O₄) were synthesized through W/O microemulsion route. The added Fe₃O₄ nanoparticles can simplify the prepared process and enhance the conductivity of nanomaterials which can increase the ECL intensity of luminophor CRuSi-Fe₃O₄. In addition, the layered structure of CRuSi-Fe₃O₄ can immobilize lots of Con A using glutaraldehyde as the coupling agent which can improve the sensitivity of the biosensor. Then the quenching probe glucose functionalized NiCo₂S₄ nanoparticles-grown on carboxylic graphene (NiCo₂S₄-COOH-rGO@Glu) was anchored on the modified-electrode via the specific carbohydrate-Con A interaction. Here, NiCo₂S₄ was used to quench the ECL of CRuSi-Fe₃O₄, graphene was used to grow NiCo₂S₄ nanoparticles as carrier materials and glucose was served as the recognition element for bounding Con A. Therefore, a desirable quenching ECL signal was measured with S₂O₈^2- as the coreactant of CRuSi-Fe₃O₄. Under the optimization of determination conditions, a linear response range for Con A from 0.5pgmL^-1 to 100ngmL^-1 was obtained, and the detection limit was calculated to be 0.18pgmL^-1 (S/N=3).