Fluorescence resonance energy transfer system between znse nanoparticles encapsulated by silica and gold nanoparticles for detection of dopamine

A fluorescence resonance energy transfer (FRET) system consisting of ZnSe nanoparticles incorporated by a silica shell (ZnSe@SiO₂ as donors and AuNPs as acceptors was proposed. AuNPs are non-covalently absorbed on ZnSe@SiO₂, leading to a significant fluorescence quenching due to the FRET between the ZnSe@SiO₂ and AuNPs. The quenching locks in the fluorescence of ZnSe@SiO₂ and provides an off state for a “turn on” assay. In the presence of neurotransmitters such as dopamine, these molecules can interact with AuNPs via covalent binding of their amino groups, which leads to the dissociation of AuNPs from the ZnSe@SiO₂ surface and the consequent restoration of the ZnSe@SiO₂ fluorescence. In order to evaluate the present system as a biosen-sor media for the detection of dopamine, photoluminescence (PL) spectroscopy was employed to analyze ZnSe@SiO₂-AuNPs. Indeed, when the system was conjugated with dopamine, a significant enhancement of the fluorescence occurred and the PL intensity was a linear function of the dopamine concentration in the range of 5–25 ppm with a correlation coefficient of 0.9809.