A novel ECL biosensor for the detection of concanavalin A based on glucose functionalized NiCo2S4 nanoparticles-grown on carboxylic graphene as quenching probe

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 S2O82- as the coreactant of CRuSi-Fe3O4. Under the optimization of determination conditions, a linear response range for Con A from 0.5 pg mL−1 to 100 ng mL−1 was obtained, and the detection limit was calculated to be 0.18 pg mL−1 (S/N=3).