Enhanced LSPR performance of graphene nanoribbons-silver nanoparticles hybrid as a colorimetric sensor for sequential detection of dopamine and glutathione.

In the present study, a novel plasmonic sensing platform was proposed for sequential colorimetric detection of dopamine (DA) and glutathione (GSH) in human serum sample by taking advantage of plasmon hybridization in graphene nanoribbons/sliver nanoparticles (GNR/Ag NPs) hybrid. DA was detected based on etching strategy and morphology transition of label-free Ag NPs hybridized with GNR. As a result of the etching process, hexagonal Ag NPs were changed to smaller corner-truncated nanoparticles and a blue shift was observed in its plasmonic band, accompanied by the color change from green to red. Sequentially, GSH induced aggregation of Ag NPs which resulted in a decrease in absorption intensity of Ag NPs plasmonic band and a color change from red to gray. By employing GNR/Ag NPs hybrid as a sensitive colorimetric sensor, DA and GSH were successfully detected in low concentrations of 0.04 μM and 0.23 μM, respectively. The same experiment was carried out in the absence of GNR and the detection limits were obtained 0.46 and 1.2 μM for DA and GSH, respectively. These results confirmed the effective role of GNR on the sensitivity improvement of GNR/Ag NPs hybrid. The proposed simple and sensitive sensing approach offered a beneficial and promising platform for sequential detection of DA and GSH in the biological samples.