Novel SPR biosensors based on metal nanoparticles decorated with graphene for immunoassay

Novel surface plasmon resonance (SPR) biosensors based on Au-graphene (Au-Gra) nanohybrids and Ag-graphene (Ag-Gra) nanohybrids for the detection of mouse IgG were developed. The biosensors proposed are label free, and have high sensitivity and selectivity for biosensing. Au-Gra and Ag-Gra nanohybrids were synthesized in a simple, effective and rapid way, and further characterized by X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM) and UV-vis absorption spectroscopy. These nanohybrids were assembled on the Au film through 1,6-hexanedithiol by covalent attachment. And the antibody was bound to the nanohybrids through 3-mercaptopropinic acid. Some experimental conditions were determined and optimized. In the optimal conditions, the biosensors based on Au-Gra nanohybrids and Ag-Gra nanohybrids show a good response to mouse IgG in the concentration range of 0.30-40.00 μg mL−1 and 0.15-40.00 μg mL−1, respectively. While, the biosensor unmodified with nanohybrids shows a response to mouse IgG in the concentration range of 2.50-40.00 μg mL−1. As a result, the performance of the biosensor based on metal nanoparticles decorated with graphene has been improved significantly.