Sensitive and selective surface plasmon resonance sensor employing a gold-supported graphene composite film/D-shaped fiber for dopamine detection

An Au film/graphene D-shaped plastic optical fiber (D-POF) functionalized with dopamine-binding aptamer (DBA) was proposed to achieve a sensitive and specific detection of the small molecule dopamine. The surface plasmon resonance sensor combines the virtues of a D-shaped fiber, the transfer of graphene via gold film, and the amplification of the refractive index with the conformational transformation of DBA. The sensitivity of the Au film/graphene D-POF sensor (1539 nm/RIU) is higher than that without graphene in ethanol solution. The dopamine concentrations of 10−10 M to 10−6 M were measured. And the decoration of DBA onto graphene for dopamine detection with a good linearity was verified in experiments. The proposed sensor possesses high sensitivity and specificity, which will provide good application prospects for the development of biosensing in disease treatment.