A promising non-aggregation colorimetric sensor of AuNRs–Ag+ for determination of dopamine

Dopamine (DA) could reduce Ag+ to Ag on the surface of gold nanorods (AuNRs) to form Au core–Ag shell nanorods (Au@AgNRs) in AuNRs–Ag+–DA system, which caused dielectric function to change, the aspect ratio of AuNRs to decrease and longitudinal plasmon absorption band (LPAB) of AuNRs to blue shift (Δλ), as well as the color of the solution to change obviously. Thus, a non-aggregation colorimetric sensor for rapid determination of DA was developed based on the linear relationship between Δλ and the concentration of DA. The responsive, simple, sensitive and selective colorimetric sensor has been successfully applied to the detection of DA in serum, showing its great practicality. At the same time, the structures of AuNRs and Au@Ag NRs were characterized by transmission electron microscope (TEM). Meanwhile, the sensing mechanism for the detection of DA has been discussed.